



























Class 

Book 


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.GrZIo 


GopyrigMN 0 _ 

COPYRIGHT DEPOSIT. 


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/ 






















A COMPLETE TREATISE 

ON THE 

MANUFACTURE OF SOAP. 

/ 

WITH SPECIAL REFERENCE TO 

i 

AMERICAN CONDITIONS AND PRACTICE. 






BY 

u/ 

DR. HENRY GATHMANN, 

'I 

Editor of the American Soap Journal. 

3 

> j’o 

-)- 

3 » 

3 * 

SECOND EDITION. 

CONTAINING 

Many Practical Additions and Suggestions 






by a number of successful and well-known Soap Manufacturers, and illustrated 

by 101 engravings. 


NEW YORK, U. S. A. 

v 

Dr. Henry Gathmann, 9 E. 42d Street. 

1899. 

L - 
















N 


TWO COPIES RECEIVED, 

Library of Congrsas, 
Office o f the 


Dtii 6- IRoq 

■ S» »# •/ 


Register of Copyrights, 




5:i?44 


Copyright by 
HENRY GATHMANN 
1899 





MCOND COPY, 


\^o4- 

-VX .Woe 






I 


Preface to the Second Edition. 


ROM the time when the first edition of American Soaps ap- 



1 peared in print, seven years ago, the author has continually 
collected all available new information that could assist in making 
a later edition of the book more complete and that could serve to 
keep it abreast of the times. Much assistance in this respect has 
been gained indirectly from requests for special information made 
in the interval by purchasers of the original edition, questions 
which have served to show in what directions the book could be 
completed by greater details or brought up to date by newer in¬ 
formation. Besides this, many voluntary contributions and pract¬ 
ical hints have been received during the same time from numerous 
friends, for the express purpose of having them embodied in the 
new edition so long in preparation. 

As the result of these several additions, every chapter of the 
original work has been carefully revised, completed and brought 
up to date, embodying changes which in some chapters amount to 
practically an entirely new treatment of the subject. 

Apart from these substantial additions and changes made in 
every part of the work, there are three entirely new chapters on 
subjects of importance which have been added on the suggestion 
of friends some of whom had placed their order in advance for a 
copy of any new edition that might appear. 

The plan underlying the original edition of this work, namely 
to print only matter of practical importance, excluding all obsolete 
processes, theoretical methods, intricate chemistry, etc., has met 
with such favor among the practical manufacturers of soap in all 
countries, that it has been scrupulously adhered to in the present 
edition as well; the new items and changes consist of practical 
points almost exclusively. 

In respect to the (new) chapter on simple tests to be made in 
the soap factory, for the purpose of examining raw materials and 





4 


Prfface. 


products, the same plan has been followed; that is to say, on the 
ground that those equipped for elaborate tests are also provided 
with the latest literature on that subject, no attempt has been 
made to describe difficult chemical tests requiring expert skill to 
make them ; instead of that there are collected in this chapter tests 
that can be made with little difficulty by every soapmaker, with 
results at least valuable, if not always so absolutely correct as can 
in certain cases be obtained by one experienced in difficult chemi¬ 
cal work and equipped with a large laboratory. 

In short, this revised edition has been prepared with a view 
to preserve American Soaps the distinction it has already gained ; 
that of being the standard text book on the art of soapmaking as 
actually practiced in American factories. 

In conclusion, as it was a pleasant duty to acknowledge be¬ 
fore my indebtedness for numerous valuable hints and sugges¬ 
tions, to such practical manufacturers as Messrs. Geo. A. Schmidt, 
Melzer Bros., F. B. Strunz and others, so I have again to thank 
numerous friends, who have, by their recent communications 
and advice, assisted materially in bringing together the new ma¬ 
terial now added to this work, most of which now appears in 
print for the first time. 

New York, November, 1899. 


tfl vV 
IV'l/y 


INDEX OF CONTENTS. 


Introduction 


Page. 
.. 11 ) 


CHAPTER I. 
The Nature of Soap. 


Alkalies in general.1. 23 

Fats and fatty acids in general. 24 

Soap, its formation, various ingredients, &c. 25 


CHAPTER II. 

Fats and Oil's. 

Fats and oils, their effect on soap, &c. 

Rancidity. 

Adulteration of fats and oils, preliminary tests for same 

Rendering (2 illustrations). 

Tallow and bleaching same. 

Grease and bleaching same. 

Lard. 

Cocoanut oil and bleaching same ; copra oil. 

Palm oil and bleaching same (1 illustration). 

Palm kernel oil. 

Olive oil and foots ; bleaching foots. 

Cottonseed oil ; bleaching. 

Cottonseed stearin. 

Cottonseed foots ; soap stock ; bleaching. 

Linseed oil and bleaching same.. 

Castor oil. 

Wool grease ; lanolin. 

Various other oils and fats. 

Oleic acid (red oil). 

Rosin. 


31 

3r, 

35 

38 

42 

45 

47 

48 
51 

55 

56 

57 
60 
60 
62 
63 

63 

64 
66 
68 




































6 Index. 

CHAPTER III. 


Lye scale (1 illustration). 71 

Grades of alkali. 72 

Quality of Lyes. 73 

Effect of lyes of different quality, in different stock and processes. 74 

Pure caustic ; carbonate of soda. 76 

Salt. 76 

Potash... 77 

Effect of lyes of different strengths. 78 

CHAPTER IV. 

Filling Materials. 

Talc. 79 

Silex. 80 

Silicate of soda and of potash. 80 

Starch. 81 

Mineral soap stock. 82 

Soda ash, sal soda, sulphate of soda, salt, potash, borax, &c. 82 

Various other materials used in soap making. 83 


CHAPTER V. 

The Soap Factory. 

Location. 87 

Arrangement. 87 

The building. 88 

The lye tank (6 illustrations). 89 

Strunz patent lye apparatus (2 illustrations). 95 

Melting trough (1 illustration). 98 

Settling tank. 99 

Stock blower (1 illustration). 100 

Soap kettles (10 illustrations). 101 

Connections with kettles. Ill 

Soap pumps (9 illustrations). 112 

Crutchers and re-melters (11 illustrations). 116 

Sal soda tank. 127 

Soap frames (7 illustrations). 127 

Trucks (1 illustration). 132 

Slabbers and cutters (9 illustrations). 134 

Drying apparatus (2 illustrations). 141 

Presses (11 illustrations). 142 

Dies (18 illustrations), including safety devices. 149 

Chipper (2 illustrations). 164 

Mill (3 illustrations).•. 165 

Plodder (3 illustrations). 166 

Powder mills (1 illustration).'. 169 

Steam separator (1 illustration). 170 










































Index. 


7 


CHAPTER VI. 

Manufacture of Soaps. 

Page. 

Selection of materials and methods for certain soaps. 173 

Form and quality of soaps. 178 

Special properties of the soap to be made. 179 

Selection of process (cold, half-boiled, boiled, milled). 180 

Re-melted soap. 188 

CHAPTER VII. 

Settled Soaps. 

Rosin soap. 185 

Saponification of the fat. 186 

Graining. 190 

Rosin Change. 192 

Strengthening change. y . 194 

Finishing. 195 

General remarks. 196 

Framing and filling. 197 

Stripping, cuttiug, drying, &c. 201 

The nigre and its uses. 202 

Scraps. 204 

White settled soap. 205 

CHAPTER VIII. 

Boiled-Down Soaps. 

German mottled. 212 

White boiled-down soap. 220 

CHAPTER IX. 

Eschweger Soap. 

Eschweger soap. 223 

Blue mottled. 229 

Modified process. 232 

CHAPTER X. 

Soft (Potasii) Soap. 

General remarks. 235 

Stock and lye. 237 

Filling. 238 

Rosin ... 240 

The boiling. 243 

Crown soaps. 243 

Figged soaps. 245 

Artificially figged soap. 247 


































Index. 


8 


CHAPTER XI. 

General Remarks. 

Page. 

General remarks on boiling soaps. . 241) 


CHAPTER XII. 

Half-Boiled Soaps. 

Introduetion and description of process, filling, &e. 257 

Advantages and disadvantages of lialf-boiling. 259 

Half-boiled white soap. 261 

“ for milling. 262 

<< u mottled. 2613 

“ “ floating soap. 264 

“ rosin soap. 264 

“ '« tar soap. 265 

“ “ filled soap. 266 

“ “ cocoanut oil soap. 266 

“ “ transparent (see special chapter). 


CHAPTER XIII. 

Cold-Made Soap. 

Advantages and disadvantages of cold process. 269 

Selection of stock for cold-made soaps. 271 

Purity of the stock. 273 

Quality of the lye. 275 

Quantity and strength of lye.:. 277 

Temperature of stock for mixing. 279 

Mixing and saponification.;... 281 

Filling. 283 

Perfuming, coloring, marbling. 284 

Formulas for various cold-made soaps. 286 

Pure cocoanut oil soap. 286 

Filled cocoanut oil soap.. 287 

Cocoanut oil soap, filled with salt solution. 287 

Tallow and cocoanut oil soap. 287 

Glycerin soap. 290 

Lanolin soap. 291 

Laundry soaps. 291 

Rosin soaps. 292 

Tar soap. 293 

Carbolic soap. 294 

Utilizing scraps of cold soaps. 294 


CHAPTER XIV. 


299 


Re-Melting Soap 





































CHAPTER XV. 


Milled Soaps. 

Page. 

General remarks. 303 

Stock for milled soaps. 305 

The milling process.... 307 

Perfuming milled soaps. 310 

tr 

1 • 

CHAPTER XVI. 

Coloring and Perfuming. 

Coloring.,. 313 

Perfuming. 319 

Selection and preparation of the perfumes. 337 

Perfumes for laundry soaps. 340 

“ “ cold-made soaps... 341 

“ “ (boiled) milled toilet soaps. 345 

CHAPTER XVII. 

Pressing the Soap . 350 

/ 

CHAPTER XVIII. 

Special Soaps. 

Floating soap. 357 

Transparent soap.'•. 359 

General remarks. 359 

Shaving soap.. 367 

Perfuming. 370 

Tooth soap. 370 

Scouring soap. 372 

Metal polishing soap.-. 374 

Harness soap. 374 

Carbolic soap.’. 375 

Red mottled castile...*. 375 

Saltwater soap. 376 

Tar soap. 376 

Gall soap. 377 

Medicinal soap. 378 

Sulphur soap. 383 

Surgical soap. 384 

Washing powder. 385 
































CHAPTER XIX. 

Page. 

Sal Soda Making. 389 

CHAPTER XX. 

Glycerin and its Recovery from Waste Lye. 

Recovery from waste lye. 397 

/ 

I 

CHAPTER XXI. 

The Simpler Tests and Examinations in the Soap Factory. 

Alcohol. 413 

Borax . 414 

Essential oils. 415 

Fats and oils. 419 

Glycerin. 422 

Soaps. 424 

Soda and potash. 427 

Tar. 432 

Tables etc. 437 

The thermometer.. 439 

Table showing centigrade degrees and their equivalent on Fahrenheit 

scale. 440 

Appendix. 443 

Index. 451 



















PART I. 


A 
















































































* 

- 






























* 


















. 

. 
























































































































































. 

I 




















































































A Few Words to the Practical Soapmakers. 


Among - the contents of this book the practical soapmaker 
will recognize many statements of facts which, through his own 
practical experience and observation, and through his previous 
study of the subject, have become perfectly familiar to him ere 
this. If they appear here, it is of course not with a claim for 
novelty, but for the sake of completeness, and for the benefit of 
those less well informed. 

If he read the book attentively, and from the beginning to 
the end, he will undoubtedly be amply repaid for his trouble 
by finding in it also many useful suggestions which are new to 
him, and whose value he will readily admit without question. 
It being in the nature of the case that such suggestions must be 
distributed over many different pages and chapters, the soap- 
maker should not fail to read all of the book, including also such 
chapters as may treat of soaps which he does not make, especially 
so since there has been absolutely no useless padding added to 
unnecessarily swell the number of pages. 

The principal object, however, of especially addressing the 
practical soapmakers in these few lines, is to remind them of the 
fact that the time has not come yet when even the most expert 
will agree on all the practical points involved in their art, even 
under the same conditions otherwise, and that circumstances 
vary on every hand. It is therefore fully expected that the ex¬ 
perienced soapmaker will find in the practical part of this book 
more or less that he will see proper to disagree with. It is his 
privilege to criticize this work, but he should not do so until he 
has carefully read the whole book, nor without considering that 
this treatise is based on the actual experience of many of the 
most expert in the art; those practical soapmakers, therefore, 
will not be doing justice to their own best interests who refuse 



18 A Few Words to the Practical Soapmakers. 

to at least give the most serious thought to all those points ex¬ 
pressed that happen not to be in accord with the opinions they 
have held up to the present. 

In regard to the figures named here and there as to strength, 
quantity or time, every soapmaker knows from experience that 
there is hardly an operation carried out in the factory which is 
not subject to changes under varying circumstances ; the arrange¬ 
ment of the kettles and of the other machinery, changes in the 
purity of the raw materials, climate and local conditions, as well 
as the greater or less degree of care and time that can be devoted 
to the quality of the product, and the state of the market—all 
these have more or less bearing on the special figures to be in¬ 
serted into the several formulas. It is therefore insisted above 
all that in the elucidation of principles, as much as in the formu¬ 
las, lies the value of this work, if the author may make bold at 
all to presume that it has any. 


Introduction. 


Although the art of soap making reaches so far back into 
antiquity that its early beginnings are now merely matters of 
conjecture, it is only in the last hundred years that the principle 
features of the art, as it is conducted at the present day, were 
developed. 


Leblanc’s diseov* 



It is now just a century ago (1791) that Leblanc, a French' ery of artificial 


soda. 


chemist, discovered and patented a process of manufacturing 
soda from common salt, and this invention, more than any other 
influence, brought about great changes in the manner in which 
:his industty has since been conducted. 



Previous to the manufacture of this artificial soda, the alka¬ 
lies employed by the soapmaker were derived mostly from the 
ashes of various plants. Special forms of such crude alkalies 
much used formerly (and still employed to a limited extent at 
the places of their production) are barilla and kelp. The former 
is a crude soda derived from burning plants that grow along the 
shores of the Mediterranean ; the latter is a similar material 
made in more northern countries by burning several varieties of 
seaweeds. Ashes from plants growing in places more distant 
from the sea contain mostly potash, instead of soda. Leblanc, 
whose invention has been of incalculable benefit to mankind, 
died in the greatest poverty in the year 1806. 

Fifty years later (1841) another great discovery, and one of chevreui’sdiseov 
considerable influence in the soap industry also, was made by 
Chevreul—like Leblanc, a celebrated French chemist—who at 
that time discovered the true composition of fats, and who was 
first to explain correctly the nature of the chemical action by 
which soap is formed from fat and alkalies. His discovery has 
been of the greatest practical value to the fat industry, and all 
the allied branches Chevreul died only a few years ago (1889) 




20 


Introduction. 


at the remarkable age of 102 years, and, unlike the unfortunate 
Leblanc, had the satisfaction of at least reaping a substantial 
reward for his numerous useful labors. 

To the achievements of these two men, therefore, is due in 
a great measure, directly and indirectly, the enormous develop¬ 
ment of the soap industry at present. It is true that other pro¬ 
cesses for the artificial manufacture of soda have since been 
discovered and come into use, besides the Leblanc process, but 
this was at a time when the Leblanc alkali had already modified 
the manufacture of soap to a very great extent. 

Considering then the comparatively recent date of these two 
far-reaching discoveries, it is not. surprising that—particularly 
in the United States—the manufacture of soap should have un¬ 
dergone great changes in the last fifty years, especially as it is 
only since 1839 that cocoanut oil came into use for soap making, 
while cotton seed oil was not introduced until about fifteen years 
later. Fifty years ago the American methods still greatly re¬ 
sembled those employed in England, but since that time they 
have become materially changed. The New England States 
were then the principal center of the American soap industry, 
and the soaps made from the raw materials and with the appli¬ 
ances available were in many respects very different from those 
of the present time. Filling materials were practically unknown, 
and the “settled ” soap was simply run into the wooden (lift ) 
frames and crutched for hours until it became thick from cooling ; 
or it was finished by boiling down, or perhaps by “running.” 
The soap was ladeled by hand from the kettles into the frames, 
or into buckets or tubs, which were then carried to where the 
frames were placed, to le emptied into the latter. The soap 
kettles were made of cast iron bottoms, to which a wooden curb 
was fastened by means of wedges and cement, and the composi¬ 
tion of a cement that would prevent leakage for any length of 
time was then considered a great trade secret! Through the 
wooden curb just mentioned a pipe entered, which reached down 
to near the bottom of the kettle and by means of which the 
waste lye was run off. The kettles were heated by open fire and 
the contents were stirred and kept from burning or adhering to 
the bottom by means of a long iron rod, flattened at the end. 
The lye was made either by causticizing soda ash with lime 
or by leaching wood ashes, for caustic soda did not become a 
commercial article until the beginning of the present century, 



Introduction. 


21 


and was but slowly adopted for use in soap factories at first. 

The first pressed cakes of laundry soap are said to have been 
brought on the market by B. T. Babbitt, of New York. At 
that time the soapmakers also were much more generally man¬ 
ufacturing candles, lard oil, potash and soft soap than they are 
now. 

When the civil war broke out rosin became very scarce, and 
was, therefore, largely substituted by simply adding water to 
the soap ; silicate of soda was used similarly in some cases, but 
its use had not yet become general at that time. Most forms of 
adulterations of soap have become known only within the last 
half century. 

After the war, when rosin was again more plentiful, there M proveraents ^ 
was a tendency at first to return to the old methods of making 
unfilled settled soap, but soon after (some time in the sixties) 
the process of hardening resin soaps by means of sal soda was 
first introduced; its first application is ascribed to A. Van Haagen, 
then of Philadelphia. 

Gradually the process of recovering glycerin from waste 
soap lye had been perfected in England, and began to be prac¬ 
ticed and improved upon in our large soap factories here, until 
now a crude glycerin is furnished to refiners by quite a number 
of soap factories, operating by various methods, while there is 
also a constantly growing list of soap factories in which the 
crude glycerin is worked up into the refined article. 

The early beginnings of soap powder manufacturers also 
fall into this period, and at the present date have developed into 
a by no means inconsiderable industry. 

About twenty years ago white floating soap was first brought 
on the market by Proctor & Gamble, Cincinnati, Ohio. 

Naturally, during these fifty years a great number of im¬ 
provements in the equipment of factories were also made, and a 
large number of patents were secured on machinery and pro¬ 
cesses relating to soap making. Few, if any, of the patented 
processes, however, have proved useful. 

At present the best grades of soap made in America are at 
least equal to those made anywhere in the world, while in regard 
to mechanical facilities for operating on large quantities, with 
the greatest economy of time and labor, this country is acknow¬ 
ledged to take the lead. 
















































CHAPTER I. 


The Nature of Soap. 


The soaps of commerce being- essentially products of fats 
and alkali, a few preliminary remarks about these ingredients 
will not be out of place before considering the nature of soap 
itself. 


ALKALIES. 

The term ‘‘alkalies” is employed to designate a certain 
small group of chemicals which are characterized principally by 
the following properties : They are caustic (that is to say, cor¬ 
rosive, destructive, on animal tissues), soluble in water, combine 
readily with acids—whose properties they neutralize in so doing 
—and turn certain vegetable yellow colors into red. The alkalies, 
ni the order of their importance to the soapmaker, are Soda, Pot¬ 
ash, and Ammonia. (To this group also belongs Lithia, which, 
however, is of no special interest to the soapmaker). When an 
acid of any kind is subjected to the action of an alkali, there is 
formed a new compound—chemically called a “salt”—which will 
be neutral, /. e ., neither acid nor alkaline in its effect on animal 
tissues or on vegetable colors. (See Appendix, Note 1.) Soap 
is, chemically speaking, such a salt. 

The alkalies may be either “carbonated” or “caustic.” Car¬ 
bonated soda, for instance, is soda combined with carbonic acid, 
as in the case of ordinary washing soda, or soda crystals. When 
the carbonic acid is withdrawn from the latter by any suitable 
means, such as quicklime, the previously “carbonated” soda be¬ 
comes “caustic” soda. 


Alkaline Earths: Lime and Magnesia are similar to, but not 
true alkalies; they belong to a class of chemicals to which has 
been given the name of “alkaline earths,” because their proper¬ 
ties are partly identical with those of the true alkalies, while on 


Alkalies defined. 


Carbonated and 
caustic alkalies 


Alkaline earths, 




24 


The Nature of Soap. 


Composition of 
Fats and Oils. 


the other hand they range themselves with the true earths. 
Their compounds with fatty acids are soaps in a certain sense, 
but being insoluble in water, cannot be used for the purposes of 
the ordinary soda or potash soaps. (See Appendix, Note 1.) 

FATS AND FATTY ACIDS. 

The numerous fats and fatty oils of animal as well as veget¬ 
able origin, such as tallow, bone grease, lard, train oil, palm oil, 
cotton seed oil, cocoanut oil, etc.., etc., are neutral substances, 
which may be decomposed by the aid of a current of superheated 
steam, or by other suitable means, into two distinctly separate 
portions : a mixture of so-called “fatty acids” or “ sebacic acids ” 
on one hand, and the familiar substance of “glycerin” on the 
other. When a fat has been so decomposed into its constituent 
parts, the fatty acids in their uncombined state exert a distinctly 
acid effect on other substances, as may be witnessed, for instance, 
in the corrosion of metals by lubricating greases containing free 
fatty acids. The fats are insoluble in water, melt and burn 
readily, and cause permanent grease stains if applied to paper ; 
they combine with alkalies, alkaline earths, etc., to form various 
compounds. Glycerin is a neutral substance, formed by the 
combination of water with the “glyceryl” contained in neutral 
fats. 

Each fat, as is found in nature, contains several different 
fatty acids, (combined with glycerin), the principal ones of 
which are named respectively stearic, palmitic and oleic acid. 
Tallow, for instance, may be separated by pressure, suitably ap¬ 
plied, into a liquid and a solid portion, the former being prin¬ 
cipally olein (oleic acid combined with glycerin) and the latter 
a mixture of palmitin and stearin (palmitic and stearic acid, 
combined with glycerin.) Oleic acid is liquid at ordinary tem¬ 
peratures, congealing only when cooled to about 40 c F. Eauric, 
palmitic and stearic acids are solid, melting at about 110°, 144°, 
and 156 : F., respectively. According as the most solid fatty 
acids are present in larger proportions the different fats them¬ 
selves will be more solid. 

The fatty acids of any fat desired may be most easily pro¬ 
cured for examination by dissolving some soap, made of such fat, 
in water, and adding a little sulphuric acid, whereby the fatty 
acids are displaced from their combination with the alkali and 
rise—mixed with each other in proportions according to the 


The Nature of Soap. 


25 


nature of the fat from which the soap was made—to the surface 
of the solution. (See Appendix, Notes 2 and 3.) 

The “mineral” and the “essential” oils are entirely differ¬ 
ent substances in composition from the fatty oils; they have 
hardly anything- in common with the latter (except their oily ap¬ 
pearance and ready inflammability), containing* neither fatty 
acids nor g^cerin, and are incapable of forming- soaps. 

SOAPS. ’ 

The Formation of Soap : As has been said in the foregoing, 
a neutral compound is the result when an acid and a base, such 
as an alkali, are caused to chemically react upon each other. 
This is true in the case of the fatty acids as well as in that of 
the stronger mineral acids—such as sulphuric and nitric acids— 
and when a quantity of an}^ fatty acid is boiled together with an 
equivalent amount of a solution of caustic alkali in water (lye), 
the product will be the neutral compound “Soap.” It is not, 
however, necessar} T , or even desirable, to decompose the fat into 
free fatty acids and glyceryl (or glycerin)' before boiling with 
lye, in order to make soap, for acids naturally have a stronger 
affinity for alkali than for glyceryl, and consequently when a 
neutral fat is boiled with a caustic lye, the fatty acids thereof 
combine with the alkali, separating from the glyceryl-which 
in turn combines with some of the water of the lye and is, at 
the end of the operation, found in the kettle as glycerin (which 
is uncombined with the soap and simply mechanically mixed 
with the mass); in boiled soaps the gljxerin is generally separ" 
ated, together with the waste lye in which it is dissolved, in the 
next stage of the manufacture. To recapitulate the essential 
parts of the foregoing, then, in one short statement, compare 
the following two lines : 

Fats are neutral salts of fatty acids with glyceryl as a base. 

Soaps “ “ “ “ “ “ alkali “ “ 

The process of soapmaking is, therefore, essentially a substitu¬ 
tion of one base (alkali) for another (glyceryl.) In combining 
to form soap, as described, the fatty acids as well as the alkali 
lose their identity, so to speak, for the soap is not corrosive as 
was the alkali, nor is it greasy and insoluble in water, as were 
the fatty acids; from this it is evident that soap is not simply a 
mixture of alkali and fatty acids, but a true chemical compound ; 
in other words they are the soda (or potash) salts of stearic, 


Mineral and es¬ 
sential oils. 


Combination of 
fats and alkali. 


26 


The Nature of Soap. 


Definite p ro por¬ 
tions of fat and 
alkali reqiiii’ed. 


Necessity and ef¬ 
fect of w a t e r 
present in soap. 


palmitic, oleic, and lauric acids, mixed in varying - proportions 
according - to the kinds of stock used. Here now it must be re¬ 
membered that, while mixtures may be made in any desired pro¬ 
portion of one ingredient to the other, chemical compounds are 
formed always in absolutely fixed proportions. Thus a certain 
amount of fat requires a certain amount of alkali to transform 
it into soap ; if less alkali than required be used, a part of the 
fat will remain simply mixed in the soap, unsaturated by lye, 
and the product will be but incompletely soluble in water and 
of a greasy ctuiracter; if more than the required amount of lye 
be employed, it will—unless removed by subsequent treatment— 
remain in the soap as free alkali, and make the product sharp 
and caustic in the proportion of the excess present. When made 
properly, the fatty acids of the soap balance (neutralize) exactly 
the causticity of the lye, and the soap is neutral. The process 
of soap making - , therefore, consists in its principal features in 
bringing - fat and alkali into direct contact with each other by suit¬ 
able means, whereby the fatty acids combine chemically with 
the alkali to form soap, glycerin being - at the same time set 
free from the fat and either remaining - in the soap or being - re¬ 
moved by subsequent treatment, according - to the particular 
process of manufacture adopted. (See Appendix, Note 4.) 

The ordinary soaps of commerce are soluble in alcohol and 
in weak caustic lye, but insoluble in ether, benzol, petroleum 
ether, and in concentrated lye. Alcoholic solutions are trans¬ 
parent and on cooling - —if sufficiently concentrated—form a jelly, 
the basis of several soap liniments. If from such a solution the 
alcohol is expelled by evaporation the soap remains as a solid, 
transparent, non-crystalline mass. Solutions in hot water are 
clear, while those in cold water are opalescent. 

The Water in Soap: There is also required, for the proper 
formation of soap, a certain percentage of water which enables 
the particles of soap to form a compact and yet readily soluble 
mass. Other thing’s being equal, the soap is more easily solu¬ 
ble— and thereby more rapidly effective—in the proportion that 
it contains a greater percentage of water ; this proportion, of 
course, must be within reasonable limits in the product to be 
marketed, as an excessive amount would be in the nature of a 
deception from the purchasers’ standpoint, besides being sure, 
by subsequent evaporation, to render the soap unsightly and too 
light in weight. Freshly made soap washes quickly, but is apt 


The Nature of Soap. 


27 


to waste away in consequence of its greater solubility on which 
this rapid action depends. On drying* it becomes more economi 
cal for use, but a certain amount of water (bound in the crystals 
of soap) is retained under all ordinary circumstances, even if the 
soap has been kept for years and appears exceedingly dry. When 
well dried, soda-soaps become very hard and difficult to dissolve, 
and are then rather unsuitable for ordinary use. The amount 
of water contained in commercial hard soaps including that only 
admixed and that bound chemically, varies greatly, from say 
about 10 to 12 per cent, to 35 or 40 ; a greater proportion than 
the latter may be said to exceed the quantity really permissible 
for a fair commercial article. 

Dry soft (potash) soaps attract moisture from the atmos¬ 
phere. Soaps made from different fats show great variations in 
their affinity for water. 

Other Ingredients in Soap: Soap proper contains, as decribed 
above, fatty acids, alkali, and a moderate amount of water ; but 
certain other additional substances generally enter into the com¬ 
position of the commercial products, for various purposes—legi¬ 
timate and otherwise. Among these may be mentioned : Rosin, 
as a partial substitute for fats ; carbonate of soda, and other 
salts, for hardening and rendering the soap more detergent; sand, 
tripoli, pumice stone, and like substances, which aid mechani¬ 
cally in the process of cleaning; glycerin, etc., for giving 
the soap greater emollient properties ; sugar, alcohol and glycer¬ 
in, for transparency; sulphur, tar, carbolic acid, and the like, 
for medicated soaps ; colors and perfumes of many varieties ; 
silicate of soda, talc, starch, mineral soap stock, and other cheap¬ 
ening materials, etc., etc. (For further particulars on the 
“Filling” materials see Chapter IV.) 

The Structure of Soap : On a casual observation, soap ap¬ 
pears to be a perfectly homogeneous mass. But on examining it 
more closely it will be found that the various soaps present con¬ 
siderable differences in their structure, depending on the manner 
in which the} 7- were made. Cold-made soaps are the only ones 
which present a simple aggregate of microscopically small crys¬ 
tals, formed by the compounds of the different fatty acids with 
the alkali. Milled soaps have a very dense, even, grainy texture 
caused by the peculiar action of the machinery on the soap, 
which may have been made by the boiling or (more rarely) by 
the cold or half-boiling process. Boiled soaps, if framed hot 


Various ingre¬ 
dients of soaps 1 


Thevarying struc¬ 
ture of soaps 
made by various 
methods. 


28 


The Nature of Soap. 


Decomposition of 
soap in use. 


Effect of h a r d 
water in wash¬ 
ing. 


and without filling-, will crystallize on cooling-, the stearate of 
soda crystallizing-out from the more slowly cong-ealing- oleate of 
soda, the grain formed by this process being more or less modi¬ 
fied by the temperature of framing, by the materials used, and 
by the size of the frames. If the same soaps are crutched until 
they are reduced to a lower temperature, these crystals will be 
less plainly developed, or at least will be distributed more evenly 
through the mass, and therefore be hardly noticeable. If filling 
is crutched in instead of framing the soap in its pure state, it 
will in most cases destroy the crystallization and cause an almost 
homogeneous texture. 

The Effect of Soap in Washing: Just in what manner the 
soap exerts its detersive action has been a matter of much specu¬ 
lation and research. The generally accepted theory regarding 
this subject is that, when this soap is dissolved in water, it un¬ 
dergoes a peculiar form of decomposition by which the neutral 
compound is split up into two parts—an alkaline soap and an 
acid soap. The alkaline soap is soluble in water and is believed 
to act by emulsionizing* the particles of grease contained in the 
articles to be cleansed, so that the dust and dirt attached to them 
can be easily removed ; the acid soap is almost insoluble in hot 
water, but more so in the soap solution, and according to this 
theory, contributes to the cleansing effect by the particles of dirt 
attaching themselves to the flakes of acid soap and thus being 
rinsed off with the latter. (See Appendix, Note 5.) 

The Water Used in Washing: The condition of the water 
used in washing has much to do with the action of the soap. 
Hard water, containing compounds of lime and of magnesia, 
has a peculiar effect on soap, as the sulphuric or the carbolic acid 
forming a part of the compounds named are capable of decom¬ 
posing it, combining at the same time with the alkali which it 
contains, and setting free the fatty acids, which then combine 
at once to form insoluble soaps with the lime of magnesia (see 
App., Note 9). In such case the lime soap (or magnesia soap) 
formed by the reaction here described, being insoluble in water, 
appears in minute flakes, which adhere to the meshes and fibres 


*In the presence of certain substances, as alkalies for instance, a mix¬ 
ture of fat and water will form an “ emulsion,” i. e., the fat is divided into 
microscopically small globules which float in the water, giving the mixture 
a milky appearance. 



The Nature of Soap. 


29 


of the cloth and produce a yellow discoloration and ultimately 
a disagreeable odor of the clot*hes. It is a matter of every-day 
observation that soft water in washing cleanses more readily and 
leaves the clothes whiter than when hard water is used, and 
when soap is used in hard water the insoluble flakes of lime or 
magnesia soap are readily seen. (The alkali of the soap, to¬ 
gether with the acid of the lime compound which causes the 
hardness, forms a new compound which remains dissolved in the 
water and is of no especial harm.) As gradually all the lime 
or magnesia of a hard water is so decomposed by soap, the hard¬ 
ness of the water decreases. So also has the free alkali in a soap 
a tendency to precipitate the lime (by combining with the car¬ 
bonic acid contained in the carbonates of lime and magnesia gen¬ 
erally present in hard waters), and consequently to neutralize the 
hardness ; it thus happens that a soap which, on account of the 
free alkali contained in it, is very sharp when used in soft water, 
may be much less so, or even quite neutral, when used in hard 
water ; in this case a soap containing a small excess of caustic 
strength is more serviceable than a neutral soap. (See App., 
Note 10). It has been calculated that the hardness of the water 
of the Thames causes an annual loss of soap in the city of Lon¬ 
don alone amounting to considerably over half a million dollars. 

The temperature of the water used for washing has as much 
influence on the efficiency of a soap as has its degree of hardness. 
The hard soap used almost exclusively in the households of this 
country is but imperfectly soluble in cold water, the soap formed 
by the combination of stearic acid and soda being soluble only 
in water at a higher temperature. Tallow and grease are es¬ 
pecially rich in stearine, and when the soaps are made of these 
fats the use of cold water entails a loss of soap for the reason 
just given; but further than that the process of emulsionizing 
the fatty and greasy matter to be removed by washing, as referred 
to above, takes place very imperfectly only when the water used 
for washing is cold. Hot water, therefore, it is evident, is in 
every way preferable. Aside from the points involved in the 
before mentioned theory on the action of soap, the great pene¬ 
trating properties of soap solution and its lubricating qualities 
come into play in washing, and contribute largely to the thorough 
effect and prompt action. 

Various D'etergent Substances: Besides soap, a number of 
substances possessing cleansing properties have been used for 


Effect of alkaline 
soap on hard 
water. 


Effect of tempera 
ture of water in 
washing. 


Various detergent 
substances. 


30 


The Nature of Soap. 


detergent purposes, and in the case of a few are sometimes in¬ 
corporated into soap. In the earliest times wood ashes were 
used for cleansing, owing to their contents of potash. It was 
then also discovered that the action of lime increased their 
efficiency (by causticizing them.) From this undoubtedly arose 
the invention of soap making, b} 7 combining the caustic lye with 
fats. 

In some countries the juices of a great variety of plants are 
utilized for cleansing purposes, the saponaceous principle being 
variously extracted from the roots, barks, leaves or fruits of these 
plants, which in a few cases form the subject of a somewhat 
limited commerce. Quxllaia bark from Chile, for instance, is 
sometimes used for washing silk; a bulb known in California as 
amole is sometimes employed as an ingredient for soap making, 
and was used for cleansing purposes by the Indians of this 
country before they learned the use of soap from the white 
man. Yucca is another plant (a native of Virginia and Carolina) 
which has detersive properties. Among the other substances to 
be mentioned in this connection are Fuller’s earth and China 
clay, which have the property of absorbing greasy matters ; and 
the alkaline substances, borax, ammonia, silicate of soda and 
carbonate of soda, also benzine, gasoline, ox-gall, and so forth. 


CHAPTER II. 


Fats and Oils. 


FATS AND OILS IN GENERAL. 

The oils and fats, of both vegetable and animal origin, form 
a class of substances which are lighter than water, practicall}" 
insoluble in the latter, unctuous to the touch, neutral in reac¬ 
tion, and cause permanent grease stains on paper; they are for 
the greater part very similar to each other in their chemical 
composition and behavior. As they are always neutral if Tin- 
changed, an acid reaction always points either to beginning 
rancidity or to some foreign (acid) substance. The pure fats 
and oils consist entirely of fatty acids and glj’cerin, or to be 
more exact, they lack only a small percentage of water in order 
to admit of being resolved completely into these substances. (See 
App. Note 14.) Thus 100 lbs. of fat may be made into about 
97 lbs. of fatty acids and 8 lbs. of glycerin, a total of about 
105 lbs., showing a gain of about 5 lbs., which is represented by 
the water required besides the fat to form these new combinations. 
Nearly all the fixed oils and fats are almost colorless and odorless 
when in a perfectly pure state, the color and odor of the crude 
fats and oils being due to the admixture of certain foreign color¬ 
ing and other matters. Leaving, for the present, out of con¬ 
sideration this small admixture of foreign matters, whose nature 
of course varies with oils of different origin, it may be said 
that the features distinguishing the numerous fats and oils 
from each other consist in the varieties and the proportions 
of the different fatty acids present in each fat; and by studying 
the peculiarities of the small number of the more important fatty 
acids, we learn also to better understand the reasons for the 
peculiarities — from the soap makers’ point of view — of the 


Composi t io n of 
fats and oils 




32 


Fats and Oils. 


different fats of which they constitute the largest portion. As 
said before, two or more different fatty acids, combined with gly¬ 
cerin, are present in every natural fat, and every fat therefore is 
a more or less complex body. It must be understood, moreover, 
that these fatty acids are not present in the fat as free acids, 
but they are combined with the chemical counterpart of acids 
i. e., a “base,” which base in this case is the “ oxide of glyceryl ’ 
(the body which is changed into glycerin in the process of sa¬ 
ponification). The acids being thus combined to the base, we 
have in fats neutral bodies of the class known in chemistry as 
“salts.” 

Among the fatty acids only a small number are of practical 
interest to the soap maker, the others being found in very small 
proportions only in any fat. Very important are Stearic, Oleic, 
and Palmitic Acid, which are present in nearly every fat used by 
the soapmaker, and also Laurie and Mystic Acid. (See App., 
Note 6.) 

All fatty acids combine readily with the alkalies. In their 
free state, as found commercially in red oil or oleic acid for in¬ 
stance, this combination takes place almost instantaneously, even 
if the lye be carbonated (that is to say, if it be made of alkali 
combined with carbonic acid, as distinguished from caustic alkali). 
The neutral fats, on the other hand, such as tallow, grease, etc., 
require boiling for hours with lye, which must be caustic, in 
order to completely saponify them. 

Stearic Acid and Stearin: When perfectly pure, stearic acid 
is devoid of odor, color, and taste, easily soluble in alcohol, 
but insoluble in water. Its melting point is about 150° F., at 
which temperature it forms a colorless, oily substance, on cooling 
again it forms a white, brittle, crystalline mass. It is present 
as stearin (stearic acid combined with oxide of glyceryl) in nearly 
all fats, and being of a very solid consistency, the fats contain¬ 
ing a considerable proportion of it, as well as the soaps made 
therefrom, are naturally more solid than those richer in the other 
varieties of the fatty acids. The hardest fats, ordinarily known 
as tallows, contain an especially high percentage of stearic acid, 
respectively of stearin. . Fats rich in stearin are better adapted 
for making soap containing rosin than the softer fat and oils. 
Stearin is a neutral substance, dissolving but sparinglv in cold 
alcohol and, like stearic acid, is solid at ordinary temperatures. 


Fats and Oils. 


33 


Soap made from stearic acid (or stearin) and soda, is very spar¬ 
ingly soluble in cold water, but quite soluble in hot water. 

Palmitic Acid and Palmitin : These have a great resemblance 
to stearic acid and stearin respectively and, like the latter, pal¬ 
mitin is a constituent of most vegetable and animal fats, being 
especially abundant, however, in palm oil. Palmitic acid is 
somewhat lighter than stearic acid, melts at a temperature about 
12° F. below that required for the latter, and forms at ordinary 
temperatures an odorless, tasteless, colorless, brittle and crystal¬ 
line mass. It is insoluble in water, but easily dissolved by boil¬ 
ing alcohol. 

Palmitin is neutral, insoluble in water, and almost insoluble 
in alcohol; at ordinary temperatures it is a solid body, melting 
at a somewhat lower temperature than stearin. 

Oleic Acid and Olein : Like the preceding two fatty acids, 
oleic acid is found in most of the natural oils and fats. It is 
insoluble in water, but readily soluble in alcohol, and when pure 
it is devoid of odor, taste and color. It differs greatly, however, 
from stearic and palmitic acids in being liquid above 39-40° F. 
(below that temperature it is hard and crystalline), and a large 
proportion of oleic acid in any fat tends to make it more fluid. 

Olein differs from stearin and palmitin in being much more 
soluble in alcohol, also somewhat slower to combine with alkalies 
to form soap. The soap it forms with the alkalies is much softer 
and more easily soluble in water than stearin soap. 

Laurie Acid: This is a fatty acid found in cocoanut oil and 
some other oils. It melts at about 110° F., forming a thin oil 
which, on cooling, turns into a crystalline mass. 

Laurin ( = Laurostearin) melts at about the same temperature, 
but on cooling it forms a solid, brittle mass, not unlike stearin, 
it is easily saponifiable. 

Myristic Acid: This fatty acid also is found in cocoanut oil 
and in some other fats. It melts at about 129° F. and when cold 
forms a solid, crystalline mass. 

Linoleic Acid; Ricinoleic Acid; and Butyric Acid: are among 
the remaining fatty acids which deserve to be mentioned ; they 
are characteristic of linseed oil, castor oil, and butter respectively. 

Mar gar ic Acid , Cocinic Acid: In the older text books mention 
is frequently made of margaric acid ; this was at one time the 
name of what is now known as palmitic acid ; then it was applied 


34 


Fats and Oils. 


to a supposed newly discovered fatty acid. Later it was held that 
the substance then known as magaric acid was really only a 
mixture of stearic acid and palmitic acid, while at present the 
existence of a special margaric acid is again affirmed by later 
investigators. So also is cocinic acid a mixture of other fatty 
acids (lauric and myristic), and not, as was formerly believed, an 
independent acid. 


Effect of the va¬ 
rious fatty acids 
on the soap. 


As was said in the foregoing, all fats are mixtures of various 
compounds. Thus, tallow is a mixture of stearin, palmitin and 
olein. Bearing in mind the peculiarities of each of these, as 
above described, it is readily seen why melted tallow, on being 
slowly cooled, may be caused to separate into a solid and a liquid 
portion ; the stearin and palmitin solidify, at a temperature at 
which the olein still remains liquid. This fact is practically 
utilized in the manufacture of many products, such as the so-called 
oleo-oil for artificial butter, etc., the liquid olein being separated 
from the warm fats by filtering it, under pressure, from the 
solidified stearin and palmitin. In the natural oils and fats the 
solid portions may therefore be considered as being dissolved in 
the liquid part, and on cooling slowly the stearin, etc., separate 
out from the olein, etc., partly by solidifying on account of the 
low temperature, and partly by crystallizing. 

It must not be supposed, however, that a fat acts in every 
manner directly in accordance with the peculiar characteristics of 
its constituent parts. For instance, it was stated above that 
stearic acid melts at 156° F. and palmitic acid at 144° F.; a mixture 
of equal parts of each might be supposed therefore to melt at 150° 
F.; or it might be supposed that at 150° the palmitic acid alone 
would melt, leaving the stearic acid solid. But as a fact, the mix¬ 
ture melts at 134°—a lower temperature than would suffice to melt 
either oneof the ingredients singly. Furthermore, regardingtheir 
action in soap making, the fats have a tendency to communicate to 
a certain extent some of their properties to each other; an oil, for 
instance, which combines with difficulty only with alkali, will do 
so more readily when mixed with a more easily saponifiable fat. 

On the whole, however, it is safe to select fats for soap mak¬ 
ing according to the characteristics they possess singly, with a 
view to counteract extreme effects of one fat, by the addition of 
another fat known to give opposite results. For example, soap 
from tallow alone forms a lather slowly, but the lather remains 



Fats and Oils. 


35 


a long- time; and soap made from cocoanutoil alone lathers very 
readily, but the lather formed is of very short duration ; but if 
both fats are used together, they quickly yield an abundant and 
lasting lather. Tallow soap, during the boiling and later op¬ 
erations, has a very thick consistency and becomes solid while 
still very hot, so that for carrying out certain operations requir¬ 
ing fluidity of the mass, an oil like cocoanut oil, which gives a 
soap of thin body while hot. is a valuable aid in the process of 
manufacture. Again, some oils form soaps which are too easily 
soluble for some practical uses, and in such case the addition of 
fats forming less easily soluble soap is indicated. These con¬ 
siderations will be further carried out in detail in the following 
description of the fats used in soap making, and also in a special 
chapter devoted to the selection of stock for soaps of different 
character. 

Rancidity of Fats and Oils: When fats are exposed for some 
length of time to the influence of the air and light, they absorb 
oxygen from the atmosphere, and a portion of them is split up 
into fatty acids and glycerine. The free fatty acids are then 
gradually decomposed still further into another series of volatile 
fatty acids of a rank odor, so that rancid fats are characterized 
by an offensive smell, and contain more or less free fatty acids. 
The presence of moisture, either in the fat or in the air, seems 
not to be absolutely required in order to render fats rancid, but 
like other foreign matters in the fat, it seems certainly to favor 
the process. Thoroughly purified fat, deprived of water, is pre¬ 
served much longer and with less difficulty than the natural 
products in their crude state. (See Appendix, Note 7.) In 
place of becoming rancid, some oils (the so-called drying oils) 
become more solid, forming a transparent varnish. 

Adulteration of Fats and Oils : It very frequently occurs that 
soap manufacturers buy fats and oils and work them up into soap 
without close examination, provided they have a good appearance, 
when these fats upon investigation would be found to contain 
impurities or adulterations which detract considerably from the 
apparent value of the fat as a soapmaking material. 

These extraneous matters may be merely accidental or frau¬ 
dulent additions, but in either case they certainly merit much 
greater attention than they are now accorded by most soapmakers, 
for whatever may be the nature of the impurity, it signifies a 


Rancidity of fats. 


Adulterat ion of 
fats and oils. 


36 


Fats and Oils. 


loss to the soapmaker in every instance, unless properly allowed 
for in the price of the material. 

Almost too well known to require special mention here is the 
adulteration (up to the point of entire substitution) of olive oil 
by cotton seed oil. A similar case is that of lard; a recent ex¬ 
amination made in Germany of lard imported from this country 
showed that out of 110 different lots no less than 77 were adul¬ 
terated more or less by the addition either of cotton seed oil or 
inferior qualities of animal fat, so that on an average the alleged 
lard was only of half its supposed money value. 

The lower priced fats, which are of greater importance to 
our soap manufacturers, such as tallow, grease, palm oil and the 
commercial fatty acids, escape adulteration no less. One adul¬ 
teration to watch for in tallow consists of mineral soap stock, 
which is an unsaponifiable residue obtained from petroleum re¬ 
fineries. Of this material 20 per cent and more may be present 
in the tallow without injuring its appearance or its consistency 
to a very great extent, and unless suspected it may not be dis¬ 
covered without a special test, for a boiled soap made from it 
would be merely a little softer, while the presence of the foreign 
matter in the soap would not be easily revealed. Used for cold- 
made soap a given weight of such stock requires less lye than good 
tallow, as the mineral impurity does not combine with lye. The 
soapmaker no doubt prefers buying pure tallow, and possibly add 
the soap stock to his soap at the price of soap stock , to paying 
for the latter at the price of tallow. 

A similar adulteration consists of glucose, of which quite 
noticeable amounts have been found in commercial tallow and 
greases. 

A still more common adulteration of fats consists in the ad¬ 
dition of water which has been incorporated by the aid of some 
emulsifying agent, such as soda, potash or lime. A very appre¬ 
ciable quantity of water may thus be worked into a fat without 
being detected, except upon close examination. Not only the 
weight, but also the solidity and the appearance of the fat are 
thus artificially ‘‘improved.” When soda or potash have been 
employed for the purpose the loss is simply one resulting from 
the low yield of soap obtained from the fat; when lime is present, 
however, a double loss results, from the formation of lime soap 
in the fat, which deteriorates the quality of the soap made from 
the latter as well as the quantity. Hager recently reported that 


Fats and Oils. 


37 


a certain lot of grease intended for soap making, upon being 
closely examined by him, was found to contain 18 per cent of lime 
soap. After saponifying and “cutting” with salt a voluminous 
precipitate of lime soap was noticed. He concludes by saying 
that the presence of lime in the fat need not necessarily be the 
result of fraud, since it is possible that pork infested with trichinae 
had been treated with caustic lime in order to insure against its 
being consumed as food, and that on rendering the fat the lime 
was thus brought into it. For the detection of lime soap in the 
fat he proceeded as follows : The fat was dissolved in a water 
bath in five times its volume of petroleum and set aside in a 
temperature of 15° C. (59° F.) In the course of eight hours a 
precipitate had formed which was collected on a filter, washed 
out with petroleum benzine and dried between filter paper. The 
dry residue is the lime soap, which is soluble in hot, but insoluble 
in cold petroleum. 

The partial saponification which is the consequence of ad¬ 
ulteration by weak lye will be apparent when the fat is melted 
on water, when little or no clear fat is thereby obtained (but a 
cloudy emulsion instead) if lye is present. 

The admixture of cheaper grades of fat to the tallow or 
grease cannot perhaps be properly called an adulteration, as it 
lowers the “grade” on which the price is based. 

Not exactly an adulteration, but rather an impurity, some¬ 
times contained in tallow, is sulphuric acid which has been used 
in rendering (for the purpose of destroying the membrane of the 
suet), and is not always fully removed. Such tallow is apt to 
be turned yellow in iron tanks, by the action of the acid on the 
iron. This is more frequently the case with tallow brought on 
the market by the small country butchers, who have less perfect 
facilities for rendering than the large slaughter houses. For 
soap made by the “Cold Process” such tallow is very unsuitable, 
as the acid present neutralizes seme of the lye and thereby causes 
disturbances in the process, and badly formed soap. Glue and 
albuminous matter are frequently found in fats as accidental 
impurities. 

In the absence of facilities for complicated tests, or as a sim¬ 
ple preliminary test for fats suspected of adulteration, the follow¬ 
ing proceeding will often give useful indications concerning the 
purity of the fat: A fair sample of the fat is melted and placed 
into a graduated glass cylinder; into the latter is then poured 


Preliminary test 
for adulterated 
fats. 


38 


Fats and Oils. 


Rendering in soap 
factories. 


about 35 parts (by volume) of dilute sulphuric acid to 100 parts 
of fat. After shaking- well, let settle. The pure fat rises to the 
top, while the sulphuric acid absorbs the impurities and settles 
to the bottom The graduations marked on the vessel will ap¬ 
proximately indicate how much pure fat was contained in 100 
parts of the sample. The line between the fat and the precipi¬ 
tate should be distinctly visible, and if it is not so, then the 
experiment should be repeated with a strong-er acid solution. 
Of course, this test is of no avail in determining adulteration 
by cheaper fats, and can only be used in regard to such additions 
as water, lye, lime, flour, etc. 

Rendering Fats : Throughout the country there are numer¬ 
ous soap factories so situated that they prefer to render them¬ 
selves the tallow and greases they require, as by this means they 
are not only placed in a position to obtain material of a certain 
uniform quality, but, under favorable circumstances, to save 
considerable money besides. 

The operation of rendering consists in removing the mem¬ 
branous tissue which envelopes the fat as it is taken from the 



Fig-. 1. 

animal carcass, thus separating the pure fat, and may be carried 
out in many different ways; at present the several methods have 












































































Fats and Oils. 


39 


mostly given way, however, to the uniform system of rendering 
by steam, under pressure. 

In former times the operation was carried out in open kettles, 01 (l methods o f 
jacketed or otherwise, over open fire, with or without the addi¬ 
tion of water, the raw fat having been previously cut into small 
pieces. This modus operandi had several disadvantages, such as 
failure to extract all the grease, the evolution of an extremely 
obnoxious odor, great inconvenience in manipulation, etc. In¬ 
stead of using a high degree of heat for the purpose of rupturing 
the cellular tissue and liberating the fat, dilute sulphuric acid 
was partly employed later on in several different ways, as this 
acid has the property of dissolving and decomposing the mem¬ 
branes; this latter process has since been all but abandoned for 
rendering any but very small quantities, and steam is now al¬ 
most exclusively employed for rendering, as follows: 

The application of steam is made either indirectly, by means 
of open steam-jacketed kettles (see Fig. 1) or by admitting it 
directly into the material operated upon in so-called digestors 
(Fig-. 2.) 

For the better grades of fat, the jacketed kettles are fre¬ 
quently preferred, as by direct contact of the steam with the fat 
the membranes are transformed into glue and the quality of the 
product is impaired. But while the quality of the fat obtained 
from rendering in jacket kettles is superior, the quantity is les¬ 
sened, and for ordinary use digestors are commonly employed, 
which have the further advantage of allowing of a higher tem¬ 
perature (by operating under pressure) than is possible in open 
kettles. 

The digestors in use are variously constructed as to details, 
but in their main features they resemble the one here illustrated 
(Fig. 2.) This apparatus is a closed, cylindrical tank, made of 
boiler iron or steel plates, riveted strongly so as to safely allow 
of a high pressure. In size it varies according to the required 
capacity, a very common size being 10 to 12 feet high, with a 
diameter of from 3 to 5 feet. 

Referring to the illustration, M is a manhole, through which 
the tank is nearly filled with the raw material at the beginning 
of the operation; this done, the tank is closed tightly. S is a 
safety valve set at the pressure intended to be used. D D D are 
cocks by which the depth of the melted fat can be determined 
and the product drawn off after the operation is finished. A 


40 


Fats and Oils 


steam gauge should be attached to the apparatus, unless a sepa¬ 
rate steam boiler can be used to supply the steam necessary, in 



Fiar. 2. 

which case the indications of the gauge of the boiler may be 
relied on. G is the discharge hole through which the ‘ ‘ tankage” 































































































































































Fats and Oils. 


41 


is removed ; instead of placing- it at the bottom, as shown in 
the illustration, it may also be arrang-ed somewhat higher—on 
the side of the tank—say half-way between the bottom of the 
cocks D, and just above a perforated diaphragm placed in that 
portion of the digestor. The diaphragm serves as a support for 
the fat to be rendered, and at the end of the operation the tank¬ 
age may be easily removed from it in case the discharge hole is 
placed on the side ; it it is at the bottom, as shown, the diaphragm 
must be made so as to tilt when the refuse is to be removed. A 
pipe is also provided on top, for carrying off the obnoxious odor 
arising from the operation ; leading this pipe into the fire-box 
of the steam boiler, between the boiler and the grate, the'odor 
is destroyed by the flames more effectually than by any other 
means so far discovered. 

When the tank has been charged as before mentioned, steam 
is admitted through the steam pipe shown at the bottom of the 
apparatus. The pressure at which the steam is used varies ac¬ 
cording to circumstances, depending on the size of the apparatus, 
the nature of the stock to be rendered, and on the time that may 
be allowed ; the higher the pressure used, the less time is con¬ 
sumed, but as a high pressure (and consequently greater heat of 
the steam) affects the product disadvantageously, it is ordinarily 
preferable to use rather more time and less pressure ; 45-50 lbs. 
in the digestor is probably a fair average of the steam pressure 
commonly used, rather less being used for low grades of stock, 
in order to avoid as much as possible the decomposition of various 
impurities which would contaminate the product. The time re¬ 
quired for steaming, of course, also varies according to the same 
circumstances which govern the proper degree of pressure, and 
may be more or less than ten hours. During this time the steam 
continuously admitted condenses into water, which collects at 
the bottom, and may be drawn off frormtime to time through the 
pipe W. 

When the operation is finished, steam is turned off and the 
contents of the digestor are given time to separate and to settle. 
The melted fat may be drawn off through the cocks D D D, the 
lower part of the tank being filled with water and with the ac¬ 
cumulated refuse. The latter is taken out, pressed to regain 
the last fat it may hold, and dried to be worked up for fertilizing 

material. 

Saponification of Fats : By saponification the soap maker 


42 


Fats and Oiis. 


usually understands the process of boiling- fats and oils with lye 
during- which soap and glycerine are formed. But the term is 
used in a wider sense also to denote any process whatever by 
which fats are split up into fatty acids and glycerin; the word 
in this.sense, therefore, includes even such processes in which 
no alkalies or any other basic substances are employed. Thus 
saponification in the latter sense (without the formation of soap) 
may be carried out by the use of water aione, at a high tempera¬ 
ture ; this process is facilitated by a small addition of an acid 
or of a base ; most readily, however, is saponification effected by 
the use of sufficient quantities of a base (soda, lime, potash, &c.) 
to combine with the fatty acids set free to form soap. Strong 
sulphuric acid is also capable of splitting up the fats. The var¬ 
ious forms of saponification, apart from soap making, are em¬ 
ployed in the manufacture of stearin candles, of plasters, etc. 
Thus a saponification with water, a few per cent of lye, and a 
high temperature (in a high-pressure apparatus) is sometimes 
used to manufacture glycerin and fatty acids, the latter of which 
are then used to manufacture candles and soaps. 

TALLOW. 

Properties of tai- Tallow, especially in this country, ranks foremost among 

low in soap male- M . , . , . 

ing . the fats used in soap making, as it posesses many properties 

which make it particularly well adapted and valuable for the 
purpose ; but, unfortunately for the soap manufacturer, there is 
a steadily growing demand for tallow for the oleomargarine in¬ 
dustry and for the lard “refineries,” so that the better qualities 
of the stock are too apt to find their way into these channels. 

Tallow consists of about one-third its weight of olein and 
two-thirds of a mixture of stearin and palmitin, and is conse¬ 
quently one of the most solid of fats. The large proportion of 
stearin also has the effect that the soap made of tallow as the only 
fat does not lather readily unless the water used with it is hot. 
(See preceding pages.) But the exact proportions of these con¬ 
stituents are variable, in consequence of which tallow varies in 
hardness. Tallow soap gives a very mild and persistent lather, 
is economical in use, and, while fresh, it is whiter in color in a 
proportion as it contains more water ; on drying it has a tendency 
to turn yellow, or even brownish, which may be to some extent 
prevented, however, by bleaching the stock, or by the addition 
of some vegetable fat—especially cocoanut oil—to the tallow, 


Fats and Oils. 


43 


whereby the drying- of the soap is also retarded. Tallow is easiest 
to saponify when the lye used at the beginning of the boiling is 
not of a much greater strength than 8-10° B., and even when 
the lye is used of this strength only, all through the operation, 
the resulting soap in the kettle will be much thicker and tougher 
than soaps of other fats would be even when made of stronger 
l} 7 e, and therefore, containing less water. 

Like all commercial articles, tallow varies very much in 
quality. Its color ranges from white to yellow ; the feeding of 
the cattle as well as the season, and the breed and age of the 
animals, each influence its hardness as well as the color and odor 
to some extent, and the different part of the animal furnishing 
it, as also the methods and care used in rendering, and the age 
of the tallow, are of considerable influence on its qualities. In 
order to extract as much tallow from the raw fat or “suet” as 
possible, a weak solution of sulphuric acid, or less frequently 
alkali, is sometimes added to the fat before rendering, whereby 
the tissues in which the tallow is enclosed are dissolved or charred, 
and the fatty matter may be extracted with greater ease. But 
the chemicals, if used in excess, or if not removed by washing 
afterwards, are apt to injure the tallow as well as to give rise to 
unforseen irregularities if used for making soap by the cold pro¬ 
cess. The steam employed in rendering is liable to transform 
the membranous matter into glue, which is then very likely to 
remain in the tallow. Moreover the moisture, particles of blood, 
etc., attached to the raw fat, rapidly deteriorate the quality of 
the tallow, so that the latter is apt to be rancid, unless rendered 
as early as possible. Considering then that tallow is brought on 
the market by large slaughtering houses as well as by numerous 
small city and country butchers, the varieties and qualities are 
easily accounted for. 

In making soap, the tallow used frequently requires to be 
bleached in order to produce the clear white color so much admired 
in certain brands. For simply clarifying the tallow it is sufficient 
to boil it on water (or open steam) to which some salt and some 
alum has been added ; but this means is not always sufficient for 
the purpose. Tallow so treated still contains more or less free 
fatty acids, which attack the iron of the kettle and thereby 
cause a yellow color of the tallow if the latter is left in an iron 
vessel for any length of time. The removal of these free fatty 
acids, which range in proportion from 2 to 10 per cent, is also 


Bleaching tallow. 


44 


Fats and Oils. 


very important when the tallow is to be used for “cold-made” soap; 
and finally the alum treatment is most effective in an alkaline 
solution, i. <?., when combined with lye treatment as described 
below. 

According- to the facilities and the requirements of the case, 
the process of bleaching is carried out in different ways. A sim¬ 
ple process, which purifies and bleaches tallow to some extent, 
is to heat it just enough to melt it in a tank which is provided 
with a perforated pipe at the bottom, through which a strong 
air current is forced into the tallow. The air rising through the 
tallow agitates it thoroughly and destroys some of the coloring 
matter; some cold lye (6 to 10% at 20-22° B., the amount depend¬ 
ing on the quality of the tallow) is then sprinkled over the tallow 
through another perforated pipe above the tank, this lye dissolv¬ 
ing a considerable amount of the foreign impurities and carrying 
them down. (This process is most effective when done at the 
lowest possible temperature.) Then turn on heat, just enough 
to separate the lye from the fat. When the fat has been agitated 
for some time with the lye, alum is added (about 1 pound to 2— 
3,000 lbs. of stock), which combines with and precipitates the 
glue contained in the tallow. The mass is crutched for a time 
longer and is then allowed to rest and the impurities settle to 
the bottom. The alum treatment is adapted for most kinds of 
fat, and should always be used in connection with lye, as the 
precipitation can be best affected in the alkaline mixtures. 

Another process of bleaching is carried out with the aid of 
Fuller’s earth. As this material causes some loss by the oil it 
absorbs, the smallest effective quantity should be used ; and as 
its effect is much impaired by water which it greedily absorbs from 
the atmosphere, (although it may then still appeal- perfectly 
dry), it may be at times very good economy to heat the Fullers’ 
earth in a steam-jacketed pan to drive off all moisture just before 
use. The tallow is heated by closed steam in the kettle, in order 
to drive out all the moisture ; next from 2to 5 per cent of thor¬ 
oughly dry Fullers’ earth is added through a sieve to spread it in 
fine division over the fat, and the mixture stirred (or agitated by 
blowing in air as described) for fifteen minutes, during which 
time the temperature of the tallow is raised to 220-230 F. The 
most thorough mixing and agitation secure the best results. The 
kettle is then covered and the mass allowed to settle for from 
six to twelve hours, when the bleached tallow may be run off 


Fats and Oils. 


45 


from the impurities that have settled out; or a filter press may 
be employed to separate the Fullers’ earth from the tallow. In the 
latter case the fat absorbed by the Fuller’s earth may be recovered 
from the press cakes by boiling- the latter by live steam under 
brisk agitation. Even the Fuller’s earth may be recovered and 
used over again, where operations are sufficiently extensive to 
warrant the trouble, by treating it, after recovery of the fat, 
with caustic soda lye to remove fat, glue, &c., skimming off the 
frothy matter from the top, sending the earth once more through 
the filter press, and drying as before. ^ See also the description 
of Fuller’s earth on another page. 

Other bleaching processes will be described in the succeeding 
pages and may be employed for tallow with more or less success, 
just as the foregoing are also applicable to cottonseed oil, &c. 

GREASE. 

The term “ grease,” as used commercially, comprises various 
fatty matters of animal origin, that cannot be classed among the 
distinctive products like tallow, lard, neatsfoot oil, etc. “ Grease'’ 
is extracted from bones (about 3%) hides, the refuse of kit¬ 
chens, hogs that have died by being smothered or frozen in 
transit, and from those parts of all classes of animats which do 
not yield fat that might be classed with tallow or lard. Ob¬ 
viously then, there are very many grades, varying in quality 
from fresh,white, and comparatively hard grease—which is better 
for soap-making purposes than the lower grades of tallow—to 
dark, soft and rancid grease which may be hardly fit for soap 
making. Generally speaking, grease ranges itself along* with 
tallow in its properties for the manufacture of soap. It contains 
the same fatty acids as the latter, but olein is present in larger 
proportions as the grease is softer and, of course, the solid stearin 
and palmitin are correspondingly less, so that grease has a lower 
melting point than tallow. 

The result is that soap made from grease is softer, and also 
that grease saponifies somewhat less readily than does tallow. 
Being generally less fresh and pure, and affected by a disagree¬ 
able odor, grease is not adapted for making soap without boiling, 
as the impurities and the odor must be removed; the free fatty 
acids and unsaponifiable impurities in rancid grease make even 
a fair result by the cold process simply impossible. Besides the 
soap from grease is darker than that from tallow. 


efinition of 
“grease.” 


roperties of 
grease in soap 
making. 


46 


Fats and Oils. 


Grease generally, and especially bone grease, is frequently 
found to contain a considerable quantity of gluey matter, lime, 
soap, water, and free fatty acids; occasionally the proportion of 
glue is so large that the stock can scarcely be made into soap at 
all. Saponified alone it forms a thin soap which is sometimes 
difficult to separate from the waste lye by the usual means of salt, 
although the grease may appear to be thoroughly saponified. 
The soap mass then forms an emulsion and may even have a sharp 
taste as if an excess of lye were present. By continued boiling, 
however, this sharpness will dissapear, and when thoroughly sa¬ 
ponified the soap may be separated by salt without trouble. 

As free fatty acids combine very readily with lye which is 
not caustic, rancid grease is frequently employed with advantage 
for using up the strength of partly exhausted lye, whereby the 
carbonate of soda in the lye is saved also. 

White Grease is made chiefly from the whole animals, with 
the exception of the intestines. The latter are rendered separ¬ 
ately and yield Brown Grease. Other fats not fit for lard also go 
to make white grease. Yellow Grease is made by packers, from 
all their refuse materials, and such hogs as may die on their 
hands. Tallow Grease corresponds to the yellow grease of the 
hog packers. These greases are sometimes pressed, to make 
grease stearine for soapmakers’ use, the oil so gained finding ap¬ 
plication in the manufacture of lubricating oils. 

Dark grease may be bleached, and its smell at least partly 
Bleaching grease, removed, by adding a small quantity of saltpeter to the melted 

grease and agitating; the saltpeter is then neutralized by care¬ 
fully adding enough sulphuric acid to decompose it. A dirty 
scum is precipitated and the grease thereby becomes lighter in 
color. Another bleaching process for dark grease is as follows : 
Melt the grease together with an equal weight of salt brine of 
15° B., to which about two pounds of alum to 1,000 lbs. of grease 
may be added to remove the glue, and boil for a quarter of an 
hour; let settle over night and draw off the clear fat from the 
sediment, into a wooden vessel, or a lead-lined tank. When the 
fat has cooled down to about 100° F. (a higher temperature in¬ 
terferes with the bleaching) add to every 1,000 lbs. a bleaching 
fluid made as follows: 5 lbs. powdered bichromate of potash (or 
bichromate of soda) dissolved in 15 lbs. of boiling water; add 20 
lbs. of fuming nitric acid of 22° and 2 l /i lbs. sulphuric acid of 
60° B. This mixture is added in a thin stream to the grease 


Fats and Oils. 


47 


while it is agitated by an air pump or crutched constantly; the 
grease first becomes dark, then gradually lighter, until a sample 
cooled on glass is of a light yellow color. If necessary this pro¬ 
cess may be repeated. After half an hour’s rest 150 lbs. of boil¬ 
ing water are sprinkled over the grease (without crutching) to 
wash out the acids, and after a night’s rest the clear grease is 
drawn off from the sediment. In many cases, however, grease 
withstands all efforts to bleach it. The rationale of this process 
is that the bichromate, on the addition of an acid (sulphuric or 
hydrochloric acid may also be emplo}^ed) develops oxygen which 
destroys coloring matter. (See App., Note 20). If sulphuric 
acid alone be used, 100 parts of potassium bichromate will re¬ 
quire 134 parts of 66° sulphuric acid. It is believed by some 
that a better effect is secured by the use of hydrochloric acid, of 
which (if of 20°) 530 parts are to be used to 100 parts of pot¬ 
assium bichromate. No effect is had if the bichromate were to 
be added to the fat and the acid thereafter. Should the settling 
out of the impurities require an excessive amount of time, it can 
be accelerated by adding a pound of alum, dissolved in 15 or 20 
gallons of hot water, after the bleaching is ended. 

LARD. 

Lard, when pure, consists of nearly two-thirds olein and a 
little over one-third stearin and palmitin, varying with the part 
of the animal from which the fat is taken. It is quite a suitable 
material for soap, as the product, while fresh, is very white, 
mild and agreeable in use; but owing to its value for cooking 
purposes lard is not generally within reach of the soap maker. 
When old, especially if steam rendered, or made by butchers 
from scraps saved up till enough are on hand to make it worth 
while to render them, it is likely to be rancid. Frequently such 
lard is also dark colored and contains considerable glue. In sa¬ 
ponifying, it behaves similarly to tallow, but the resulting 
soap requires more salt to separate it from the waste lye and 
retains less water; it is consequently more brittle than tallow 
soap, and when old it becomes rancid, even more quickly so than 
cocoanut oil soap. In Europe it is much thought of as a material 
for soap making, being there much used for toilet soaps and in 
the cold-made soaps, being considered a great improvement over 
pure cocoanut oil soaps, but in this country it has been found less 
satisfactory than tallow. Whether this is due to a different 


Composition of 
lard. 


Peculiarity of lard 
as a soap stock. 


48 


Fats and Oils. 


nature of our lard has not been ascertained, but certain it is that 
soap made from lard becomes rancid on keeping-, or, in the words 
which a soap maker who has experimented with it extensively 
spoke in disgust: “The hog- always will show itself.” 



COCOANUT OIL. 


Composition of 
cocoanut oil. 


Pecular i t i e s of 
cocoanut oil. 


This oil consists larg-ely of lauric and myristic acid, and 
some palmitic and other fatty acids in smaller proportion. Ow¬ 
ing- to this unusual composition, cocoanut oil occupies a place in 
soap-making- materials quite peculiar to itself. Among- the 
features which distinguish it from other fats is the fact that it 
requires a larger proportion of alkali to form a neutral soap than 
does any other fat or oil, palmkernel oil being next to it in that 
respect. Furthermore, cocoanut oil soap has the capacity of ab¬ 
sorbing large quantities of salts and water, so that by taking ad¬ 
vantage of this property the actual amount of soap from a given 
quantity of cocoanut oil may be made to appear several times as 
much by the addition of several salts dissolved in water. By 
reason of this ability to absorb salt solutions, it is very hard to 
separate a soap made of cocoanut oil alone from the waste lye in 
boiling, and if by means of an excessive portion of salt this ob¬ 
ject is accomplished, the resulting soap will be exceedingly hard 
and brittle and untit for use, while at the same time the hot 
waste lye will hold considerable soap in solution which will se¬ 
parate only on cooling ; unless this difficulty is overcome by using 
other fats in addition, only enough lye must be used with this 
oil to render the subsequent separation of water unnecessary. 
This is a comparatively easy matter, however, since cocoanut oil 
is unlike the animal and most vegetable fats in this, that it com¬ 
bines only with strong lyes, and much water is therefore not re¬ 
quired in boiling soap with cocoanut oil. Lye of 8-10°, such as 
might be used to begin the saponification of tallow, does not 
combine with cocoanut oil at all until it has been concentrated 
considerably by boiling and consequent evaporation of water. 
This property of combining readily with strong lye on boiling 
is not possessed to the same degree by the animal fats; but cocoa- 
nut oil is able to communicate it to the latter, so that a mixture 
of tallow and cocoanut oil, for example, will readily saponify 
with lye much stronger than 10° B., as required for tallow alone. 
(These remarks on the strength of lye are based more especially 
on the lower grades of caustic soda, such as are still used quite 


Fats and Oils. 


49 


largely in some soap factories. With the high gradesof caustic, 
the strength of lye for different fats is of less consequence.) 

The soap formed by cocoanut oil and lye is much more sol¬ 
uble than soaps made from animal fats, and it therefore lathers 
very freely, even in cold water ; but the lather is thin and of short 
duration. For tender skins a continued use of cocoanut oil soaps 
is irritating, a result due perhaps more to its great solubility and 
consequent concentrated effect, than to any inherent quality of 
the oil itself. A disadvantage of cocoanut oil is the disagreeable 
odor which it develops with age, even when made into soap with 
other fats, and which is an offensive characteristic of many other¬ 
wise good brands. The soap furthermore is brittle, but hard, 
and cocoanut oil is therefore a very suitable addition to so-called 
weak stock, (fats yielding a rather soft product, as cotton seed 
oil, grease, etc.) It is more than any other soap soluble in hard 
water and in sea water, by which property it has earned the name 
“marine soap.” Cocoanut oil, when boiled with lye, forms a 
soap which is very much thinner than a tallow soap containing 
the same percentage of water, and when it is used in combina¬ 
tion with other fats in a soap which is required to have a some¬ 
what thick consistency while in the process of manufacture—as 
in mottled soap—the contents of the kettle must be boiled with 
less water than is permissible in a soap made of animal fats alone 
in order to produce the requisite consistency. Lastly, cocoanut 
oil soap is what may be described as “meagre,” distinguished 
from soap made from tallow or lard, which appears much richer 
or fatter. It will be seen from the above that cocoanut oil soap 
is in many respects just the opposite of the soaps made from 
other—and especially animal—fats, and that for many uses a 
mixture of the two kinds of fat yields a product superior to that 
of either alone. 

Fresh cocoanut oil has a white color and a peculiar but not 
disagreeable odor; it melts at about 90° F., but while it grows 
older the melting point gradually rises, so that old oil does not 
melt below 110° and over. The oil brought to this country is 
chiefly of two varieties ; Ceylon oil and Cochin China oil. The 
latter oil, owing to the more careful seasoning of the nuts and 
better treatment of the oil, is the whitest, and generally in a 
fresher state than the Ceylon oil which is, or was formerly nearly 
always rancid and does not give as white a soap as Cochin oil, 
even when fresh. At present there are a few manufacturers of 


Peculiarities o f 
soap sfrom co¬ 
coanut oil. 


Ceylon andCochin 
cocoanut oil. 


50 


Fats and Oils. 


Ceylon oil who prepare it more carefully, so that it now some¬ 
times is nearly as white and fresh as Cochin oil. On the other 
hand Ceylon oil makes a harder soap and binds a larger quantity 
of water, so that it may be bleached and used instead of Cochin 
in case of necessity, by using- slig-htly more water to soften the 
soap. For cold made soap cocoanut oil, and especially Cochin 
oil, is a favorite material for various reasons, such as its readiness 
to combine with strong- lye, its lathering- qualities, its ability to 
hold larg-e amounts of adulterations, and the beauty of the colors 
when used in such a soap, but for such purposes the oil should 
be not too old. 

For bleaching it, the following- process may be used: Melt 
the oil in a kettle, and add three pounds of salt to 100 pounds of 
Bleaching cocoa- boiling- with open steam (or where no steam is available use 

brine at 15 to 20° B., instead of dry salt) and skimming- off the 
dirty scum rising to the surface until it gradually becomes white. 
By this operation mucilagenous and other impurities are removed, 
but if the oil is to be used for cold soap, and the free fatty acids 
therefore require to be removed also, a quantity of 38° lye should 
be added first and warmed with the oil (as described under Tal¬ 
low bleaching), before commencing the salt treatment, and the 
soap formed skimmed off. The amount of lye to be used for 
this purpose depends, of course, on the amount of free fatty acids 
in the oil; 3 to 4% of lye will ordinarily be sufficient. 

This proceeding is sometimes modified, somewhat similarly 
as described under tallow, as follows: Bring the oil to 150° F., 
crutch in well 4% of 36° lye ; after crutching for half an hour 
add 4% salt solution of 20°, and crutch till well separated; then 
settle and draw off the clear oil; clean the crutcher, return the 
oil into it, heat to 120 c and add for 100 lbs. of oil: 1 lb. alum and 
2 lbs. salt previously dissolved in 20 lbs. of water ; crutch half 
an hour, settle, draw.off the salt water and sediment. 

Another method of clarifying cocoanut oil consists in bring¬ 
ing it to a boil with 200 lbs. 8° B. carbonate of soda solution and 
100 lbs. water to 1,000 lbs. of oil, and letting it settle. Still 
another way, recently introduced, is carried out by using a 25° B. 
silicate of soda solution, of which 20 to 25 lbs. are added to 1,000 
lbs. of oil and brought to a boil; then a strong salt solution is 
at once sprinkled on the surface and a few hours’ rest allowed, 
when the soap formed may be skimmed off and used for some 
common soap. The clear cocoanut oil should be allowed a few 



Fats and Oils. 


51 


days rest thereafter, in case it is to be used for the cold process 
of soap making-. 

Cocoanut oil is made from the fresh pulp of the cocoanut,\ 
usually in the country of its growth; or the nuts are shipped as 
ballast in vessels returning- from tropical countries, and worked 
up into oil in other countries. 

There is, however, another variety of the oil, which is made copra on. 
from the dried pulp, or “copra,” in Europe, and to a smaller ex¬ 
tent also in this country (New England). It is quite similar to 
the ordinary cocoanut oil, but not so white as the Cochin or 
Ceylon oil, and therefore preferably used for colored soaps ; this 
is especially so if the copra was dried by fire, instead of by the 
sun, whereby it acquires a yellow shade. Still another variety 4merio . in 
is made in this country by several manufacturers of dessicated nut oil. 
cocoanut, who employ the milk of the nuts for this purpose. 

The oil made from it has a lower melting- point and is further 
distinguished from the ordinary cocoanut oil also by a peculiar 
odor. 


PALn OIL. 

Palm oil ranks next to, and resembles tallow in the quality Composition and 
of soap made from it, particularly when the oil has been bleached. pa im oil. 
Consisting of palmitin, olein, and considerable proportions of 
free fatty acids of the same compounds, it yields a firm soap that 
lathers more readily than tallow soap ; but when old, palm oil 
soap, like tallow soap, becomes hard and lathers but poorly. 

Even when saponified with weak lye of say 8° B. the soap in the 
kettle is thick and tough ; but stronger lye is used for its saponi¬ 
fication in practice. With the exception of tallow, palm oil con¬ 
tains the largest proportion of solid fatty acid (palmitic acid in 
this case) of all tbe fats, so that soap made from it is of a solid 
consistency, even though it readily holds a rather large propor¬ 
tion of water, and lathers freely. 

Palm oil is liquid in warm countries, but in cooler climates 
it has a consistency similar to that of lard, melting at from 80 c 
to 105° F. and over, according as it contains more or less free 
fatty acids, the melting point becoming higher with age. In 
color it varies from orange to brown, and sometimes—although 
not so often now as in former years—even almost black; the odor 
of the fresh oil is quite pleasant, being not unlike that of orris 
root, while old oil may have a very disagreeable smell. The 


52 


Fats and Oils. 


odor of the fresh oil harmonizes well with most perfumes and is 
not destroyed in making- soap, unless previously removed in the 
process of bleaching- the oil by chemicals; nor is the color des¬ 
troyed by alkali, althoug-h the oil is readily bleached by air and 
and light, or chemicals. The addition of palm oil to the stock 
also causes an improvement in the odor of rosin soaps. Exposed 
to the air the oil rapidly becomes rancid and paler in color; but 
the presence of the larg-e percentage of free fatty acids—which 
is not infrequently found to be as high as one-third of the total 
—can only be accounted for by the irrational methods of manu¬ 
facture followed in many districts whence the oil is obtained. 
Palm oil is the product of the fruits of several species of palms, 
more especially of that known as Elceis Guineaensis, which grows 
in profusion in West Africa, (Guinea) and other countries. The 
so-called palm nut is of about the size of a walnut and consists 
of a kernel enclosed in an oily, fibrous envelope. The latter 
yields the palm oil, and from the kernel is made the palm kernel 
oil so largely used in European soaps, and described hereafter. 
The ripe nuts are thrown into a hole in the ground, for keeping 
until the oil is to be made, and in the meantime they seem to 
ferment slightly, so that they yield an oil of a high melting point 
or so-called “hard” oil, which naturally contains more free fatty 
acid than the “soft” oil as made in certain other districts of 
Africa from the fresh nuts. Little or ft no care being taken to 
free the oil from the dirt adhering from storing the nuts in the 
ground, the oil made as described contains generally quite an 
appreciable admixture of foreign matter. When sufficient nuts 
have accumulated, they are boiled to soften the fiber and then 
bruised and covered up with leaves for twelve hours. Consider¬ 
able heat is thereby generated spontaneously, and the oil partly 
runs off and partly is washed and pressed out. The oil is then 
boiled in order to free it from the water taken up in washing, 
and thereby assumes a still darker color. 

Lagos palm oil is by far the best grade, not only from natural 
causes, but also because it is made more carefully and less sub¬ 
ject to adulteration. It is therefore less rancid and also has the 
best color. On very hot days, if the packages have been dam¬ 
aged somewhat in transit, this grade is less liable to leak out of 
the barrels than is the case with lower grades of palm oil. 
Lastly it is the best grade for bleaching. Next to it in grade is 
the so-called old Calabar oil. 


Fats and Oils. 


53 


Unbleached palm oil yields a soap of yellow color, but on 
exposure to the air this color generally fades from the surface of 
the cake, until at last only a small yellow spot remains in the 
center. This may be prevented, however, by using - some rosin 
in the soap, which gives it the property of holding the color. 
Crude palm oil must not be used in soap, however, to an extent 
exceeding say 15% of the total of the fats used, because in large 
proportions the color is very apt to stain the clothes in washing, 
the yellow spots so caused being very difficult to remove from 
the clothes. 

For light colored soap the palm oil of course requires bleach¬ 
ing, which then, the coloring matter being destroyed, permits 
the use of larger proportions of this oil. This process may be 
performed either by the influence of light and air or by chemi¬ 
cals. By bleaching according to the first named process which 
is hardly effective though with the poorer qualities of the oil, 
the odor of the oil is retained, while bleaching with chemicals, 
unless done with the greatest care and with the smallest amount 
of chemicals, destroys it. Previous to bleaching the oil it is 
melted and heated by open steam for thirty minutes or more, or 
melted on boiling water, or melted and some lye crutched in to 
purify it; after settling and cooling to 125° F. the oil is drawn 
from the water and sediment. By then heating it to 212 c F. 

and forcing air currents through 
it by means of a perforated pipe, 
or by pumping the hot oil through 
a perforated pipe and letting it 
fall back into the tank, the color¬ 
ing matter is destroyed. The 
bleaching by air currents is per¬ 
formed more rapidly than by a 
force pump even, by the use of a 
suction apparatus as illustrated 
herewith, (Fig. 3). In it C repre¬ 
sents the steam suction arrange¬ 
ment; on opening valve b the air 
is drawn from the upper part of 
the closed tank and replaced by 
atmospheric pressure through 
pipe F. K K is a closed steam 



Fig. 3. 


coil for warming the oil. The tank is charged through the man- 


The coloring mat¬ 
ter of palm oil. 


Bleaching palm 
oil. 












































54 


Fats and Oils. 


Bleaching palm 
oil by the use of 
chemicals. 


hole above and discharged through the val^e H, through which 
samples are withdrawn also to watch the progress of bleaching. 
If desired pipe E is provided with means for heating the air 
passing through it, whereby the bleaching process is materially 
facilitated, requiring only two or three hours. In the absence of 
a pump or air suction apparatus for the purpose a basket may be 
substituted which is weighted down with a stone and sunk into 
the oil and drawn up again, so that the oil trickles back into the 
tank in fine streams; this manipulation is continued till the oil 
is bleached and will require several hours longer and more work, 
of course, than the use of air currents, say 10 to 12 hours. Or 
heating it to about 300° F., or slightly over, and keeping it at 
that temperature for several hours without agitation will also 
destroy the color, and the oil will become white, with only a 
slight brownish tint. The latter process saves mechanical work, 
but unless there are facilities for bringing the oil to the temper¬ 
ature required by means of steam, it is dangerous, as the kettle 
over an open fire might leak slightly, and thus give rise to seri¬ 
ous accidents, or again it might darken the oil instead of bleach¬ 
ing it. 

The bleaching proceeds much more rapidly, however, and 
more effectivelv, by the use of chemicals, and as this requires no 
special facilities or arrangements of any kind, it is ordinarily 
preferable to the bleaching by air when only occasionally small 
lots are to be bleached. The oil, after being purified by hot 
water or by steam, as above described, (to remove coarse dirt 
that would interfere with bleaching), and cooled to 100-120° F., 
is run into a wooden vessel or into a lead-lined tank (the casks 
in which the oil comes are suitable), and for each 1,000 lbs. are 
added a saturated solution of 8 lbs. bi-chromate of potash (or of 
soda) dissolved in boiling water, and 20 lbs. strong hydrochloric 
acid, and say 4 lbs. of sulphuric acid, the mass being well agi¬ 
tated for ten to fifteen minutes, by any suitable arrangement; 
these chemicals are mixed together first before adding them to 
the oil, the oil first turns black, but gradually becomes lighter, 
and at the end of fifteen to twenty minutes the process is finish¬ 
ed. After half an hour’s rest the clear oil is drawn off and heat¬ 
ed, together with a little water sprinkled over the surface to 
wash out the foreign matters; cover and settle and draw off the 
oil for use. Sometimes less and sometimes more of the chemi¬ 
cals is required, while some prefer to use only hydrochloric acid 


Fats and Oids. 


55 


and leave out the sulphuric acid. Instead of bi-chromate of pot¬ 
ash there may also be used the bi-chromate of soda, which is 
cheaper and soluble in warm water. As all strong - chemicals 
affect the quality of the oils, it is always best to use the smallest 
amount of the bleaching - agents that may be likely to do the 
work, and then, if not sufficiently bleached by the first operation, 
to repeat it once more with a smaller amount of chemicals. 
Whenever a sample taken of the oil that is undergoing the pro¬ 
cess of bleaching shows no improvement over a sample taken 
shortly before, then the operation is finished, so far as the 
amount of chemicals used is concerned. The sediment remain¬ 
ing still contains much oil which may be regained by washing 
with hot water to which some sulphuric acid was added. The 
oil so recovered is dark colored but may be made into a fairly 
light colored soap. 

In the bleaching by chemicals disagreeable fumes arise, and 
in bleaching by air a fine yellowish material pervades the at¬ 
mosphere of the room and settles on everything, so that at times 
the wearing of a moistened sponge or other form of respirator is 
to be recommended to those engaged about the work. 

PALMKERNEL OIL. 

The kernel of the palm nut contains a large percentage of 
an oil, which is not, however, extracted to any extent in the 
countries where palm oil is made. But thousands of tons of the 
kernels are annually shipped to Europe and are there worked up 
for the oil, whence small amounts of it are also sent to this 
country. The oil is white to yellowish and of an agreeable odor, 
but easily becomes rancid. In its effects and properties in soap 
making it occupies a position intermediate between tallow and 
cocoanut oil; like the latter it saponifies most readily with strong 
lye and requires nearly as much alkali for its saponification; the 
soap is capable of holding a large proportion of salts and water 
(although only about one-half as much as cocoanut oil; it is difficult 
(though less so than cocoanut oil soap) to separate from the 
waste lye by salt; and the soap lathers similarly to that of cocoa- 
nut oil, which it also resembles in the manner of working in the 
kettle. The oil consists of the glycerides of lauric, stearic, 
palmitic and oleic acids, the first acid named constituting nearly 
40% of the oil, in which it resembles cocoanut oil. 


Peculiarities o f 
palmkernel oil. 


56 


Fats and Oils. 


Great value of 
olive oil. 


Definition of olive 
oil “foots.” 


OLIVE OIL. 

Although not used for soap making in this country to any 
considerable extent, olive oil deserves at least a brief mention in 
these pages, since it is not only an eminently suitable material 
for soap, but has given to Castile soap that reputation from 
which it derives considerable credit even now, though much of 
the Castile soap of commerce at the present time is as innocent 
of any olive oil as is the cotton seed oil which is now so largely 
sold for the product of the olive. 

Pure olive oil is pale yellow or greenish yellow, and con¬ 
tains, when cold pressed, about two-thirds olein, one-third palm- 
itin and very little stearin. If pressed with the application of 
heat it will be richer in palmitin. It saponifies readily with lyes 
of every strength, though in practice that at 20 to 25° gives the 
best satisfaction. Saponified, it forms a white or greenish soap, 
very mild and fatty, but lathering sparingly, especially in cold 
water, and becoming very hard with age. In hot water, how¬ 
ever, it is peculiarly soft and then washes away quite rapidly. 

This oil is used largely for soap making in Spain, France, 
Italy 'and other countries in southern Europe where the olive 
grows. In recent years olive growing has developed somewhat 
in California, but not sufficiently as yet to be of importance to 
our soap manufacturers. The oil used in soapmaking is that 
which is obtained from a second pressure after the table oil has 
been obtained in the first pressure. A greenish oil yielded by a 
third pressure after heating is also used in soaps and better 
known—especially in Europe—by the name “sulfur oil,” which 
name, however, also covers a product mentioned below and ex¬ 
tracted by means of carbon bisulphide. 

OLIVE OIL FOOTS. 

By this name an oil is brought into commerce from Europe, 
and imported to some extent into this country, which is partly 
extracted from the residue left in pressing the olive, as well as 
from decayed olives, and partly consists of the dregs that deposit 
from the pressed oil on standing. To extract this oil from the 
residue, bisulphide of carbon is employed, in which the oil is 
soluble. The solvent named being very volatile, it is distilled 
off again, and a low grade of oil remains, which constitutes the 
bulk of the “foots.” Olives that have been pressed cold once 
or twice for the best oil are also pressed a third time, together 


I 


Fats and Oils. 57 

with water, and the resulting 1 oil deposits a turbid sedimenton 
standing which also goes into the foots, so that the product 
known by this name is of a somewhat indefinite character. It is, 
however, always characterized by a disagreeable odor, a dark 
green color, a thickly fluid consistency, the presence of more or 
less vegetable mucous and a larger proportion of palmitin than 
is contained in the olive oil. It also frequently happens that Pr ecaution 
quite appreciable amounts of the bisulphide of carbon are left in ed 
the foots, which renders care in their use necessary, for not only 
is the vapor of this substance exceedingly inflammable, but it 
has occurred that those engaged in using the foots for soap 
making have been overcome by the vapor given off on boiling 
or melting them. 

The color of the olive oil foots and the impurities may be Bleachlng 

Oil foots. 

removed, to a great extent at least, by blowing steam into the oil 
through a perforated coil at the bottom of the vessel until the 
color gradually becomes quite light; during a few hours of subse¬ 
quent rest a dark colored slime settles out, when some strong lye 
is sprinkled over it through a perforated pipe above the vessel 
and the oil allowed to settle again. 

A more effective process of preparing the foots for soap mak¬ 
ing is as follows : Boil the foots on brine of about 12° B. until 
the dirty looking scum which at first rises, and which must be 
taken off, no longer appears. Let settle over night and draw off 
the clear oil from the sediment into a wooden vessel. Now mix 
for each 1,000 lbs. of oil 20 lbs. of peroxide of hydrogen with 3 
lbs. of sal ammonia, and warm this mixture ; then pour it in a 
fine stream into the oil, which must be continuously crutcbed 
while the bleaching liquid runs in and until brown streaks appear 
on the oil. Next the oil is at once washed with say 250 lbs. of 
boiling brine at 5° B. and left to settle again. The clear oil has 
then acquired a yellow color and will make good, common, light 
colored soap. 

Unbleached foots yield a green soap, but this color sometimes 
changes to a dirty yellow, while at other times it remains, so that 
it is frequently supported by the addition of green coloring mat¬ 
ter. In warm water this soap softens considerably and washes 
away very fast. 


r e - 
their 


olive 


COTTON SEED OIL. 

This oil has been familiar to the soap makers generally for 


58 


Fats and Oils. 


Crude cotton seed 
oil. 


Refined oil. 



Slimmer yellow. 


the past 40 years only^as previous to that period the extent of 
the production of oil from cotton seed was very small, and the 
first soaps made with it were very unsatisfactory, its proper sa¬ 
ponification not being- assured by the ordinary methods then in 

use^j 

The crude oil is a thickly fluid, dirty yellow to reddish oil of 
greatly varying quality, as the seeds from which it is obtained 
may be of good or of poor quality, according to the season ; they 
may have been stored for a considerable length of time, perhaps 
even had become damp or heated and begun to decay, and they 
may have been handled in the oil mill and expressed with differ¬ 
ent degrees of care. Some mill men obtain 33 gallons of oil from 
a ton of seed while others get 45 according to their own state¬ 
ments, which is in itself evidence of great difference in quality. 
The lower grades of crude oil generally contain a higher percent¬ 
age of free fatty acids and therefore present a greater loss in re¬ 
fining ; they also yield a lower quality of refined oil. On stand¬ 
ing for some time a slimy deposit separates from the crude 
oil. 

C^Owing to the coloring matter and other impurities contained 
in it the crude oil is not well adapted for soap making, but re¬ 
quires refining^) This operation is generally carried out in special 
oil refineries which obtain the crude oil from the mills. The pro¬ 
cess of refining consists in warming the oil to 100-115° F in 
large tanks, 15x25 feet, and adding under constant agitation, 
through a perforated pipe above the tank, about 2 per cent, of 
say 30° lye. The exact quantity, nature and strength of the lye 
used—whether soda or potash, entirely caustic or partly carbon¬ 
ated—depends on the quality of the oil and the judgment or 
preference of the refiner. The fatty acids and the lye combine 
rapidly to form a crude, black, and dirty soap which envelops a 
large amount of coloring matter ; these soap particles will settle 
in the course of 24 hours and leave the oil above sweet and light in 
color. If then found necessary, more lye may be added to purify 
the oil still further. When the oil is sufficiently refined, it is 
either allowed to rest at once, or first boiled up with about 1 per 
cent of salt previously dissolved in hot water, to assist clarifica¬ 
tion ; the impurities which settle to the bottom consist of partly 
formed soap, coloring matter, mucilagenous slime, and water or 
waste lye. The clear, pale-colored oil is drawn off, and washed 
out with water, and constitutes the grade known in commerce 



Fats and Oils. 


59 


as “ summer } T ellow.” The sediment is brought on the market- 
as “ soap stock ” or “ foots.” 

The oil when refined as above described, consists of palmitin 
and olein, the former largely separating out at a low tempera¬ 
ture. When the oil is chilled, a more liquid portion (mostly 
olein) may be separated from it, which is very suitable for a salad 
oil and known as “winter yellow,” and required to remain limpid 
at a temperature of 32° F., the more solid portion—about 25 %— 
(mostly palmitin) is brought on the market as “ cotton stearin.” 
By the latter name there is also sold another product, namely 
the solid fatty acids from factories making glycerin from cotton 
seed oil. Unless this is borne in mind the term is apt to confuse. 

Further treatment of the summer and winter yellow oils with 
2 to 3% of Fullers’ earth, with thorough agitation and subsequ¬ 
ent filtration through a filter press, furnish the “summer white” 
and “ winter white” varieties. From the facts that crude oils 
vary considerably and are refined by methods as the refiner thinks 
best adapted to their character, it is readily seen that refined oils 
also differ in quality to some extent, though less so of course 
than do the crudes. More or less thorough settling directly after 
refining and before barrelling is also a source of difference in 
qualify. 

Cotton seed oil, and especially the refined article, saponifies 
with difficulty, and only gradually by long continued boiling with 
an excess of alkali; but the process may be hastened by the ad¬ 
dition of other fats or of some soap scraps. The resulting soap 
is of a white color while fresh, and rather soft, so that the oil is 
generally used together with fats that form a more solid soap. 
In order to make a firm bar soap from cotton seed oil alone it is 
therefore necessary to finish it so that the soap should contain 
but little water. When the soap grows older it turns yellow, ac¬ 
quires a somewhat disagreeable odor, and, worst of all, certain 
varieties become covered with yellow blotches. This latter phe¬ 
nomenon seems to be due to an unsaponifiable substance (hydro¬ 
carbon) in the oil, which is not removed by the process of refin¬ 
ing, but remains and finds its way into the soap, and under fav¬ 
orable circumstances is brought to the surface by the “sweating” 
of the soap. Curiously enough, these spots do not appear in the 
“boiled-down” soap of cotton seed oil, nor in “cold-made” soap 
containing silicate of soda, and are kept somewhat in check by 
sal soda filling; but on the other hand they are very pronounced 


Foots. 


Winter yellow. 
Cotton stearin 


Properties of cot¬ 
ton seed oil for 
soap making. 


60 


Fats and Oils. 


Bleached oil. 


Composition o f 
foots. 


Mannerof saponi¬ 
fying foots. 


'in white “settled” soap soon after the same has been made. In 
rosin soap they are less noticeableT? 

The commercial refined oil may be bleached if required, by 
the use of Fuller’s earth, or by potassium bichromate and hydro¬ 
chloric acid, both processes having- been described in the preced¬ 
ing pages in connection with the subject of tallow and palm oil. 
Bleaching, however, does not prevent the before-mentioned yel¬ 
low spots in the soap. 

COTTON SEED STEARIN. 

As was said under cotton seed oil, there is separated from 
the latter at a low temperature a portion of the solid palmitin, 
and this is brought into commerce as “cotton seed stearin.” It 
is white, of about the consistency of cocoanut oil, and is a suit¬ 
able material for soap making, as it gives a firmer bar than cot¬ 
ton seed oil; but in all other respects it has the same properties. 

By cotton stearin is also sometimes understood the fatty 
acids of the oil, separated in some glycerin factories. This 
would be a good material for soap makers also, but for the fact 
that it saponifies so rapidly that unsaponified particles become 
enclosed in clots of thick soap, in consequence of which it is 
difficult to work properly. (For particulars in regard to the 
saponification of this material see under “Red Oil.”) 

COTTON SEED FOOTS. SOAP STOCK. 

The yellowish to dark brown sediment separated in refining 
cotton seed oil consists of variable proportions of imperfectly 
formed soap, water, coloring matter and dirt, from which it 
naturally follows that it is by no means of definitely fixed qual¬ 
ity. It comes on the market as “soap stock” or “foots,” al¬ 
though the latter name, properly speaking, refers to the dregs 
naturally settling from the crude oil. When made from oil 
pressed from decorticated seed it can be made into a fair grade 
of soap, but oil from undecorticated seed is so charged with 
coloring matter that the soap stock produced by refining it is 
hardly amenable to bleaching. On saponifying it in the kettle 
it turns almost black, and the spent lye is very dark. In order 
to make soap as light in color as can be effected without bleach¬ 
ing of the stock, (bleaching being possible by the use of tin 
crystals or several of the other bleaching processes described in 
this chapter), the saponification of the foots must be so con- 


Fats and Oils. 


61 


ducted as to wash out with the waste lye as much of the color¬ 
ing- matters as possible. For this purpose care is taken in the 
first change never to allow the soap to become quite neutral, but 
always to have an excess of alkaline strength in the kettle, 
whereby the coloring matters once absorbed by the lye will re¬ 
main in the same and not be incorporated in the soap. The 
waste lye from a previous boil, even if quite dark, may be used 
to advantage when beginning the saponification, as the glycer¬ 
in contained therein assists in dissolving and removing the 
coloring matters. The waste lye may be run into the kettle, 
and while adding the foots an excess of strength is all the time 
kept up by also running in more lye. When the stock is all 
saponified and the soap still has a small excess of strength, it is 
grained with strong salt solution, and after a short rest the dirty 
lye is drawn off as hot as possible. Now another change of lye 
may be given; or if rosin is to be used, the soap is first boiled 
with the lye required for the same—using some spent lye again 
if convenient—and then adding the rosin, either all or part of it 
only if 2 or 3 changes are to be made. An excess of strength is 
again kept up till the last, as before. When all is saponified 
“pitch” and use the nigre in the next batch. 

When *using this nigre it is first grained on salt water or 
with dry salt; then sufficient stock is added to almost—not quite 
—neutralize the strength. Now the waste lye is drawn off, and 
then the proceeding is repeated as before. 

Another method of making a light-colored soap from this 
material consists in bleaching the soap formed by its saponifica¬ 
tion. This process is carried out by boiling the completely 
formed soap, having an excess of strength, on a solution of hy¬ 
pochlorite of soda of 15 to 20 u B. (This solution may be pre¬ 
pared by turning free chlorine gas" into a cold caustic soda lye 
until the latter is saturated with it.) When the soap “opens” 
it is allowed to settle, the waste lye drawn off, and after the soap 
has been “closed” again by running in water, the above treat¬ 
ment is repeated, until the desired color is obtained. Care is 
necessary always to have an excess of strength in the kettle, as 


*This gas, liquefied by pressure, may be bought in iron drums holding 
about 220 lbs. each. It may be used for bleaching oils and fat, by making 
an aqueous solution and agitating it, together with the stock, in a wooden 
vessel. 


Bleaching soap. 



62 


Fats and Oils. 


Yieldof soapfrom 
foots. 


Action of linseed 
oil in soap. 


Lathering quali¬ 
ties. 


Bleaching linseed 
oil. 


otherwise hypochloric acid will form and damage the kettle. 
This process is not entirely satisfactory, but gives fairly good 
results. 

In place of by chlorine gas, this process may also be carried 
out by the help of ordinary bleaching powder which is dissolved 
in water, treated with 11 lbs. 90% alkali to each 15 lbs. of bleach¬ 
ing powder, and the whole warmed up to 125 F. Carbonate of 
lime precipitates on resting and the clear liquor is used similarly 
as is the hypochlorite solution just mentioned. 

Soap stock may be used alone, but is generally employed in 
combination with the cheaper grades of grease and tallow. A 
peculiar feature of this material is in the yield of soap it affords, 
which must be taken into consideration in calculating the cost. 
While all other kinds of stock, by reason of the alkali and water 
used, yield an increase of soap estimated roughly at about 50%, 
soap stock which only contains from say 40 to 60% of fatty acids 
furnishes only about its own weight of soap, as it already con¬ 
tains considerable alkali, besides the water and impurities v 7 hich 
are lost. 

A.s to the color of the soap, what has been said in that res¬ 
pect of refined cottonseed oil is true also of the foots. 

LINSEED OIL. 

Linseed oil consists of 10% palmitin, 10% olein and 80% 
linolein. Like cotton seed oil, it requires to be thoroughly well 
boiled with lye in order to be completely saponified; if any unsa¬ 
ponified linseed oil should be left in the soap, yellow stains and 
a rank odor will develop in time; but there is no unsaponifiable 
matter in the pure oil, at least none that causes yellow spots. 

Linseed oil alone makes a rather soft soap, but a small per¬ 
centage of it used together with other fat, such as tallow, furn¬ 
ishes a soap yielding an exceedingly fine lather. It is therefore 
used in this manner in some special brands of toilet soap. 

In Europe it is very largely used for soft (potash) soaps. 

Linseed oil may be bleached by sulphuric acid, by crutching 
into it 4% of this acid (66° B.) previously diluted with one part 
of water to four parts of acid. After crutching for thirty 
minutes the oil gradually assumes a dark green color, and is then 
allowed to rest for half an hour. Boiling water is next sprinkled 
over the oil, without crutching. A few days rest is then allow¬ 
ed, when the oil will be clear and ready to be drawn off for use. 


Fats and Oils. 


63 


Another way of bleaching- it, better adapted for soapmaking 
by the cold process, consists in treating- it with lye and alum, in 
the same manner as described under Tallow Bleaching-; a rather 
larg-er proportion of alum must be used in this case. 

The sulphuric acid and alum treatments may also be com¬ 
bined, thus: For 100 g-allons of oil prepare a solution of 20 lbs. 
of sulphuric acid (66° B.) in 2)4 g-allons of water; in a separate 
vessel place 2 lbs. of commercial alum dissolved in 2^2 gallons 
of water. Crutch in the dilute sulphuric acid so as to mix very 
thoroughly, and then follow with the alum in the same manner; 
crutch for three hours longer and then let settle. Next day 
draw off the clear oil from the top. 

The bichromate method of bleaching as described for grease 
is applicable to this oil also. 

CASTOR OIL. 

This oil consists of ricinolein, with a small percentage only Peculiarities of 

, . , r o y castor oil.' 

of stearin and palmitin. It saponifies very readily with strong 
lye, giving a hard, tough, white transparent soap, remaining . 
hard even with a large percentage of water. It lathers very 
little, however, and is therefore used only with other fats, when 
it is for the object of giving transparency to a soap, or when use 
is made of the fact that, owing to its density, it gives to soap an 
even texture and fine gloss; especially in milled soap the use of a 
small proportion of castor oil is in many cases very advisable. 

There are several qualities of this oil, expressed either hot several qualities, 
or cold, which must be selected according to the soap to be made 
the hot pressed oil being somewhat yellow and therefore better 
adapted for colored soap, while the cold pressed oil is almost col¬ 
orless. A peculiarity of castor oil is that it is completely solu¬ 
ble in alcohol; it is also the most thickly fluid of all oils. If 
there is any doubt of the oil being fresh enough for transparent 
soap, a small sample should be saponified separately with half 
its weight of 38° of lye in the cold; if a smooth soap results the 
oil is suitable; if not, it should be rejected for this purpose. 

WOOL GREASE. LANOLIN. 

Wool, in its raw state, contains a peculiar compound con¬ 
sisting of about one-half of wool grease and nearly one-half of 
carbonate of potash; large quantities of commercial potash are 
annually derived from this source, in the course of washing the 


64 


Fats and Oils. 


wool. The ordinary wool grease of commerce is used mostly for 
dressing leather, being hardly suitable for soap making owing 
to the large percentage of unsaponifiable matter it contains, its 
dark color, and its naturally unpleasant odor, which is still fur¬ 
ther increased by the remaining odor of the solvents (benzine, 
ether, etc.) used in its manufacture. It cannot be used alone to 
make into soap, but is occasionally used in Europe in the manu¬ 
facture of rosin soaps. 

wool a special purified neutral wool grease containing also a 

grease for sup- . ° . 

erfatted soaps. large portion of water and known as “lanolin,” is manufactured 
in Germany and imported from there; it is greatly recommended 
for use in ointments and pomades. Soapmakers have also em¬ 
ployed small proportions of it, together with other fats, but 
mostly in an experimental way only, and for the purpose of “su- 
perfatting” soaps. The anhydrous purified wool fat is a similar 
product used for similar purposes; it is also known as “Adeps 
Lana?,” and specially adapted to ue incorporated into soap by 
milling. It is yellowish, translucent, of slight odor only, soft 
at ordinary temperature, and has the peculiar property of readily 
penetrating the skin (hence its usefulness in ointments. &c.); it 
is neutral and does not turn rancid. It cannot be saponified by 
ordinary lye, but saponifies (at least partly) when an alcoholic 
lye is used. It differs from ordinary fats in not being a com¬ 
pound of glycerin, (See Appendix, Note 2), although the unpur - 
ified wool fat contains some glycerin. 

Distilled wool grease is said to have been used at times to 
adulterate tallow. 

VARIOUS OTHER OILS AND FATS. 

In the foregoing pages the oils and fats used more or less 
extensively for soap making in the United States have been de¬ 
scribed; there are also a number of other oils which, being used 
for the same purpose in foreign countries, are mostly of casual 
interest only in the United States. But we cannot pass them by 
without at least mentioning them. 

Neatsfoot Oil gives a fine, white, but rather soft soap. 

Fish Oils , of various kinds, yield soaps, of a disagreeable 
odor, and are only used in very common grades of soft soap. 

Sesame Oils ; the finer qualities of this oil obtained from the 
seeds of Sesasum indicum , &c., growing in warm countries, are 


Fats and Oils. 


65 


used for table oil, while the ordinary grades are used extensively 
for soap making in Europe. The cold-pressed oil forms a rather 
soft soap, but the solid part separated at a low temperature yields 
a firm bar. It is frequently adulterated with peanut oil, and in 
turn is used itself to adulterate olive oil. 

Peanut Oil is used largely in Europe, and especially in France, 
for making soap. The first cold pressure of the peanut yields a 
fine straw-yellow table oil. Oil of the second pressure (with cord 
water) is used mostly for illuminating purposes. A third, warm 
pressure yields the oil used for soap making. For this purpose 
the oil is not unlike cotton seed oil in its action and product, but 
the soap has no yellow stains. Hot pressed peanut oil is some¬ 
what dark colored, but may be bleached by treating with lye. 
The manufacture of this oil has in late years had some attention 
also in the United States. 

Hempseed Oil is used in soft soap, to which it gives a green 
color. 

Sunflower Seed Oil is used largely in Russia for hard and soft 
soaps. 

Colza Oil. This oil is used to some extent in soft soap. 

Fulleds Fat. The soap used in “fulling” textile fabrics 
constitutes such large amounts that in some places the fatty 
acids are recovered by treating the waste waters of the factories 
with mineral acids; the latter acids combine with the alkalies to 
soluble compounds, while the insoluble fatty acids rise to the 
surface, mixed with more or less coloring matter, and may be 
collected, purified as far as possible, and used over again for 
lower grades of soap. (For the saponification of such materials 
see under Oleic Acid and Rosin). 

Corn Oil. This oil is pressed from the germs that have been 
separated from the corn used in distilleries and glucose and starch 
factories. It is, or was, until a high duty was collected on it, 
exported from this country to Germany, to be employed in place 
of linseed oil for making a soft soap, as the soap formed by it is 
rather soft and yellowish. It may also be used in place of lin¬ 
seed oil, as a small addition toother fats, in making toilet soaps, 
to which it imparts good lathering properties. At present only 
a comparatively small quantity of this oil is made, and used 
mostly for tanning and lubricating purposes. It is a yellow, 
rather thickly fluid oil, consisting of some stearin, but mostly 


66 


Fats and Oils. 


Saponified and 
distilled red oil. 


olein, and palmitin, and some unsaponifiable matter and requires 
to be well saponified in order that the soap may not become 
rancid in a short time. For its saponification a strongly caustic 
lye is required. 

Horse Fat. Horses are very poor in fat, the only notable 
quantity being- found in the neck; this fat is yellow and more 
solid than lard, containing about 25% olein and 75% solid fat; 
it is usually rancid and of bad odor, but may be considerably im¬ 
proved by treatment with lye, as described under tallow. 

Almond Oil , expressed from almonds and peach and apricot 
kernels, is difficult to saponify in the cold process, unless saponi¬ 
fication is assisted by the addition of tallow or cocoanut oil in 
considerable proportion. After a series of experiments made in 
this respect on the part of a manufacturer of almond oil, the 
following conclusions were arrived at: Almond oil may be puri¬ 
fied by boiling on weak lye and separating with 20 c salt solution; 
it may then be made into a fine soap by crutching into 100 parts 
of the oil: 34 parts soda lye and 17 parts potash %e of 38 c B., at 
a temperature of 75-80 F., after crutching for an hour, let rest 
and crutch for a few minutes hourly. If the batch is begun in 
the morning, it is treated in this way through the day, let rest 
in a warm room through the night, and crutched through again 
thoroughly next morning; soon the soap is ready to be run into 
the frame. The frame must be in a warm room where, after 
about 48 hours, saponification has set in; it will take 36 to 48 
hours more for the soap to harden. 

OLEIC ACID. (RED OIL). 

When tallow is worked up for the manufacture of glycerin 
and stearic acid, for the use of candle makers, the oleic acid is 
brought into commerce separately, under the name of “red oil,” 
and used quite largely in soap making. According as the fat has 
been decomposed by distillation, or by treating it with a current 
of steam, the oleic acid is known as “distilled,” or as “saponifi¬ 
ed,” orelaine red oil (the separation of a fat into glycerin and 
fatty acids being technically termed “saponification”). The 
name “red oil” is derived from the red color which the acid as¬ 
sumes, partly by age, and partly by its action on the iron parts 
of the machinery used in its manufacture. The distilled red oil 
comes over when grease is distilled; it is thinner than the sapon- 



Fats and Oils. 


67 


ified red oil and contaminated with by-products of the process. 
The saponified red oil is pressed out from the mixture of fatty 
acids, which results from splitting 1 up a fat by means of steam 
currents, as just stated; it is the better material of the two var¬ 
ieties. 


Red oil is of a consistency approaching that of lard, and 
made into soap it furnishes a rather soft and very soluble pro¬ 
duct, for which reason it is in favor with the textile manufac¬ 
turers, who require a soap that will dissolve completely and read¬ 
ily in water of a low temperature. For bar soap it is used most¬ 
ly to make the “German Mottled” soap, for, being boiled down, 
this variety contains less water, and is consequently harder and 
less wasteful in use than ordinary soap of the same stock. 

Being a fatty acid, it does not—like neutral fats—require 
caustic lye to form soap, but will combine directly with carbon¬ 
ate of soda, driving the carbonic acid out of its combination with 
the alkali in doing so. In practice, however, caustic soda is pre¬ 
ferable, as the carbonic acid eliminated from the carbonated lye 
would make the soap frothy and spongy. 

But since fatty acids combine almost instantly with alkali, 
the order of procedure in the case of red oil is reversed when sap¬ 
onifying, i. <?., the lye is first run into the kettle and then the 
fatty acid is gradually added. If it were done in the usual way 
of running the lye into the melted stock, the soap would “bunch” 
(form in lumps, in which would be enclosed particles of the red 
oil) so that the lye would be unable to act properly on the stock; 
the soap would then form imperfectly and be very difficult to 
handle in the kettle. It is, however, an advantage to use lye 
containing some carbonate of soda, or even salt, which makes 
the soap more liquid and more mobile during the boiling. On 
the other hand, red oil may be employed to advantage for utiliz¬ 
ing the carbonate of soda which is contained in the waste lyes, 
resulting from saponifying neutral fats with lye made of the 
lower grades of caustic. In saponifying red oil strong lye of 25° 
B., or over, is used; weak lyes are apt to cause frothing of the 
soap in the kettle. 

The use of rosin together with red oil improves also the odor 
of the resulting soap (and the same is true regarding palm oil). 
One part of palm oil and two parts of red oil will yield a firm 
soap of much more agreeable odor than red oil alone. In course 


Properties for 
soap making. 


Red oil may be 
saponified with 
carbonated al¬ 
kali. 


Precautions in sa¬ 
ponifying red 
oil. 


Red oil for titiliz- 
ingcarbonate in 
lye. 


68 


Fats and Oils. 


Rosin not unlike 
red oil in com¬ 
position. 


Rosin supports 
the color of 
palm oil soap. 


of time all soaps containing- red oil become darker in color than 
they were when fresh. 

ROSIN. 

Rosin, a material left when distilling- turpentine, is a pro¬ 
duct of the pine lands of Georgia, North and South Carolina, 
Florida, and other Southern States. The sap of the pine tree 
thus furnishes the products known collectively by the time-hon¬ 
ored name of “naval stores,” i. e ., oil of turpentine and 
rosin, tog-ether with tar, pitch, and charcoal derived from 
the wood itself. The first year when a tree is tapped the sap 
runs from it in a clear white state and, on distilling-, yields the 
lightest colored rosin; with each succeeding year the sap coming 
from the tree is darker and consequently and also as the result of 
more or less dry distillation the rosin obtained from it is also 
darker. There are consequently the following grades of rosin, 
beginning with the highest grade : 


w. w. 

.— 

Water White. 

W. G. 

— 

Window glass. 

N. 

— 

Extra pale. 

M. 

— 

Pale. 

K. 

— 

Low Pale. 

I. 

— 

Good No. 1. 

H. 

— 

No. 1. 

F. 


Good No. 2. 

E. 

— 

No. 2. 

D. 

— 

Good strain. 

C. 

= 

Strain. 

B. 

— 

Common strain. 

A. 

— 

Black. 


Rosin is in some respects not unlike oleic acid, especially in 
that it is saponifiable with carbonate of soda, for rosin is a mix¬ 
ture of several acids (sjlvicand pinic acid &c., See App. Note 
12,) and—as said under red oil,—these do not aosolutely require 
the use of caustic soda, although the latter is for several reasons 
preferable to the carbonate in practice, as already stated. Soap 
made with rosin, and especially with that of the darker grades, 
becomes darker with age, while soap made from unbleached palm 
oil retains its yellow color w 7 hen rosin has been used with it, al¬ 
though without the addition of rosin the color of such soap would 
soon fade on exposure to the air and light. Rosin alone cannot 


Fats and Oils. 


69 


be made into a solid soap, and it softens every soap made of oils, 
or fats into which it enters, and renders the same more easily sol¬ 
uble, so that it is best to use it in connection with fats rich in 
stearin which has a contrary effect. For this reason the rosin 
soaps are so popular in this country, as they are serviceable even 
when well dried, whereas a soap made of tallow alone, for in¬ 
stance, would become hard and practically insoluble. While 
fresh they wash more rapidly than any other soap, and will clean 
clothes which tallow soap fails to clean. All rosin soaps, how¬ 
ever, have this disadvantage, that with age they become sticky, 
especially if the proportion of rosin used is large, appearing al¬ 
most like a soap containing unsaponified rosin, although they do 
not become rancid, as some other soaps do, For use in hard, or 
in cold water, rosin soaps are most serviceable, being second 
only to cocoanut oil soap in this respect. 

For saponifying rosin, lye of about 20° B. may generally be 
used to advantage, as weak lye causes it to froth; but it will en¬ 
ter into combination with weak as well as with strong lye. 

Being slightly soluble in salt water, more or less of the rosin 
soap is contained in the hot waste lye after saponifying the rosin 
and graining the soap with salt. On standing for some time to 
cool off this waste lye throws out of solution quite an appreci¬ 
able amount of soap, which may be regained in this manner. 

The color of rosin varies from a light yellow to a very dark 
brown and almost black, and this naturally affects the color of 
the soap made from it. By using some carbonate of soda with 
the lye employed for saponifying the rosin, a soap of lighter col¬ 
or will be obtained than when a very caustic lye is employed. 
The question of color in rosin soap will be referred 1o again in 
the following chapters. 

For special occasions rosin may also be bleached by melting 
it, to let the dirt settle, and boiling the clear rosin once or twice 
on salt solution of 10° B. for an hour or so, running away the 
dark colored brine; 20 pounds of salt solution are used for 100 
pounds of rosin. Many other methods for bleaching rosin have 
been devised, but taking labor, time, steam, &c., into considera¬ 
tion, it is questionable whether this would ordinarily pay for the 
difference in color obtained. 

The employment of rosin has frequently been referred to as 
an adulteration of soap, even by soap makers themselves. This 
is certainly not justified by any means, as a consideration of the 


Rosin is best used 
with fats rich in 
stearin. 

Advantages of 
soa£> containing 
rosin. 


Rosin soap in 
waste lye. 


Bleaching rosin. 


Rosin not an 
adulteration. 


70 


Fats and Oils. 


facts in the matter will readily show. First of all; the yellow 
rosin soaps are so very extensively made simply because the de¬ 
mand for them is greater than for any other kind of soap for 
laundry and general household purposes; this in itself would 
seem to demonstrate that rosin confers some desirable properties 
on soap. Secondly, the fact that rosin is cheaper by the pound 
than fats and oils does not of itself make it an adulteration, so 
long- as it is used in proportions suitable for the purpose. Third¬ 
ly, as rosin consists of acids that are capable of forming- a soap, 
its use can no more be considered an adulteration than the use of 
red oil, or cheap grease would be. Rosin can therefore be consid¬ 
ered as an adulteration only when the soap is supposed to be 
made of hig-h priced fats alone, and a corresponding- price is paid 
therefor. Certainly no soap, other thing's being- equal, will do 
washing at as low a cost and with as little effort as a soap will 
do which contains a moderate proportion of rosin. For use in 
cold water, or in hard water, rosin soap is in many respects un¬ 
surpassed. The rather agreeable odor of rosin soap as compared 
with a pure tallow soap also deserves mention. 

In combining- with lye, this material yields an amount of 
soap slightly below that g-ained from a like amount of fat; the 
exact g-ain cannot be given, as the commercial grades of rosin 
vary greatly. 

(Rosin oil, obtained by redistilling rosin, is a hydrocarbon 
compound, and not saponifyable). 


CHAPTER III. 


Lye. 


Lye is a solution of alkali in water, and may be of greatly 
varying- composition, as regards strength as well as quality . The 
more alkali is dissolved in a given quantity of water, the heavier 
will of course become the lye, and for ordinary use the strength 
of lye is therefore gauged directly by its weight. Avery conve¬ 
nient instrument for the purpose of ascertaining the weight is a 
“hydrometer” or “alkalimeter” (see illustration), which 
is a glass tube, closed at both ends, and provided with a 
weight on one end and a graduated scale on the other; the 
latter serves to show how deep the instrument sinks into 
the lye, being so graduated that it indicates 0 in pure 
water, and higher numbers (degrees) as it sinks less 
deeply in the liquid, or in other words, as the lye becomes 
stronger. As the instruments commonly sold do not al¬ 
ways register quite correctly, variations of a degree or so 
being by no means rare, it is well to compare new instru¬ 
ments with those already in use, before breaking of the 
latter throws all the responsibility on a new hydrometer 
whose accuracy was not tested. The graduation, as 


bx 

£ 


mostly used in this country, was designed by Baume, and the 
strength of alkaline and other solutions is therefore generally 
described as being “so many degrees Baume,” meaning that the 
instrument described sinks to that degree of its scale into the lye. 
In England a different graduation, namely that of Twaddle, is 
more generally in use. 

In order to form a correct idea of the real strength of any lye 
it is, however, necessary to also consider the nature or quality of 


Quality and 
strength of lye. 


Strength alone is 
no real indica¬ 
tion of the char¬ 
acter of lye. 













72 


Lye. 


the alkali of which the lye was made, for the alkalies of commerce 
are brought into the market into several grades, containing vary¬ 
ing proportions of pure caustic alkali, and since they correspond¬ 
ingly contain varying proportions of carbonated alkali, salt, sul¬ 
phate of soda, and other impurities, it follows that two lyes of 
the same weight may differ considerably in their nature as well 
as actual strength, even though the indications of the hydrometer 
be the same in both. 

Moreover it is necessary to take into account the fact that 
the density of the same liquid varies with its temperature. The 
difference of a lye at 60° F. as against the same lye at boiling 
point is to 4° on Baume’s scale; this is of little moment in 
making boiled soap but becomes important when testing the 
strength of lye to be used in the cold or half-boiled process, or 
for transparent soap. 

It should hardly be necessary to say that where accurate 
testing is necessary, the instrument should be dry, and especially 
free from grease, before placing it in the lye; carelessness in this 
respect is as bad as the use of incorrect instruments, and has 
caused many batches of cold soap to be spoiled. 

In order to be a little more explicit we must now consider the 
commercial varieties of caustic and carbonated soda and potash. 

Grades of Alkali'. Caustic soda is brought on the market in 
commercial grades named respectively 60, 70, 74, 76, and 77% the highest 

grades of alkali. . . . 

and almost chemically pure commercial grade of caustic soda be¬ 
ing the 77% grade. To understand these denominations it must 
be remembered that 100 lbs. of pure caustic soda are formed by 
the combination of 77% lbs. of sodium oxide with 22% lbs. of 
water, and as the percentage of sodium oxide in a sample is the 
numuer expressing the grade, it follows that chemically pure 
caustic would grade 77 %%. Itshouid also be remembered that this 
mode of indicating the grade is in use in England and in the 
United States, while in Germany the percentage of sodium car¬ 
bonate , which would be equivalent to the oxide, is named as the 
grade; iriFrancestillanothernotationis used which itis not neces¬ 
sary to describe here in detail. (See Aop. Note 8). On a sim¬ 
ilar principle as in the case of caustic soda are also designated 
the grades of carbonate of soda (soda ash etc.) and the analog¬ 
ous compounds of potash, so that soda ash ranges from 25 to 58 
per cent in grade. 

As to ordinary commercial American potash, its composition 




Lye. 


73 


is but too often a somewhat mysterious one, as very variable pro¬ 
portions of soda alkali, common salt, and sometimes lime are pre¬ 
sent. Unless an article of known purity be purchased, it will be 
necessary to carefully examine the potash used in order to obtain 
expected results. While a grade containing- 70% of potassium 
hydrate on an average is insisted on by larg-e buyers, lots are 
frequently found that averag-e only 60% and less, containing- a 
correspondingly high amount of ordinary salt. A good grade, 
moreover, is generally opaque, of dull gray or slate color, often 
with green or red stains, and is sometimes honey combed, while 
that containing much salt has a much better appearance, being 
nearly white, pearly and translucent, so that potash is very like¬ 
ly to be misjudged by its appearance. These remarks do not 
apply to the uniform products imported from Germany and 
France which are sold under a strict system of grading. 

Quality of Lyes : To illustrate more plainly the difference in 
lyes made of the various grades of caustic, let us look at the com- 


position of the latter: 

There are contained in 

100 lbs. 

of commercial 

Composition o 
CB-UStlC caustic of differ 

soda of 

60-62% 

70-72% 

77% ent grades. 

(Pure) Caustic Soda, about.. 

. 73 lbs. 

86 lbs. 

97 lbs. 

Carbonate of Soda, about.. . . 


2lbs. 

lbs. 

Ordinary Salt, about. 


5 lbs. 

fz lb. 

Sulphate of Soda, about. 


4 lbs. 

/4 lb. 


And small quantities of other substances, such as sulphite and 
silicate of sodium, etc. 

The composition as shown above is subject to slight varia’ 
tions, but at all events the table shows that a lye made of 60-62% 
caustic soda is of a very different character than one made of 
70-72% caustic, even though both indicate the same strength on 
the hydrometer. This difference is of course still greater with 
soda of 76%, and is moreover of much greater practical impor¬ 
tance to the soap maker than is at present realized in many in¬ 
stances. In fact this difference can hardly be sufficiently empha¬ 
sized or made plain enough, for the erroneous belief is very wide¬ 
ly and persistently held that not only the quality of a lye could 
be told by the hydrometer, but that even caustic could be tested 
by observing whether or not a given amount of it dissolved in a 
certain amount of water will show a certain degree on the hy¬ 
drometer; such belief is entirely without foundation. 








74 


Lye. 


Effect of foreign 
saltson tliesoap 
in the kettle. 


The best grades 
required for the 
cold process. 


Lye for saponify¬ 
ing red oil and 
rosin. 


Grades of caustic 
commonly used. 


Effect of Lyes of Different Quality : The ordinary salt, the 
sulphate and the carbonate of soda, etc., contained in the alkali, 
being' unable to form a chemical combination with the neutral 
fat or oil, remain simply mechanically mixed with the particles 
of soap formed during- the process of soap making-, (the carbon¬ 
ate of soda may combine, however, under favorable circumstan¬ 
ces, with free fatty acids, if any are present), and the presence 
of this admixture has in the first place the effect of rendering the 
soap in the kettle more mobile and liquid. When fats are boiled 
with a very high grade of caustic soda, that is to say with soda 
containing but a very small proportion of foreign salts, the re¬ 
sulting soap will be comparatively tough and thick, more diffi¬ 
cult to manage in the kettle, and of a more or less brittle grain 
when finished. The greater mobility of the fluid soap when boil¬ 
ing, if the lye used was made of medium or low grade caustic, is 
an advantage in promoting the contact of lye and fat. In the 
“cold process” of soap making, however the reverse, is true, for 
in consequence of the necessarily limited time allowed, and the 
imperfect and slow motion of the mass during the operation of 
mixing, the best cold-made soap naturally results when the high¬ 
est grade of caustic lye is employed, so as to permit the thorough 
contact of lye and fat, without the interference of foreign inert 
matter. As rosin and red oil, unlike the neutral fats, combine 
with carbonate as well an with caustic soda, mobility while boil¬ 
ing these materials with lye is insured by either the addition of 
salt in the kettle, or by taking care that there always be a sur¬ 
plus of uncombined lye in the kettle, which then—until it com¬ 
bines—has a similar effect, as the carbonate has when neutral 
fats are being saponified. In boiling soap a medium grade 
(70-72%) of caustic is therefore most generally employed al¬ 
though many prefer 60% caustic to the higher grades, for all 
ordinary purposes, as the foreign salts in this grade cause easier 
and freer working in the kettle; still others use the medium 
grades and add salt to the lye while boiling, to obtain the same 
result, a practice which is as strongly condemned by some soap 
makers as it is recommended by others. The lower grades are less 
economical in use, as will be explained below, and ordinarily 
have no particular advantage for soap making purposes over the 
medium grades. Where waste lye is to be worked up for glyce¬ 
rin the foreign salts present in it sometimes form a considerable 
item in respect to the cost of their separation. The carbonate 


Lye. 


75 


of soda of spent lyes may be utilized by boiling’ some red oil or 
rosin or rancid fat. on the lye after all the caustic strength has 
been bound; unless this is done the carbonate will be lost in the 
waste lye that is run away. 

The various salts contained in commercial caustic soda, 
which are incapable of combining - with fat, furthermore have 
this property that on dissolving - in water they render the latter 
more and more incapable of holding - soap in solution, so that 
soap may be separated from its solution in water by adding 
enough salt, carbonate of soda, or even an excess of strong - caus¬ 
tic lye, to the contents of the kettle. 

The presence of moderate quantities of foreign salts in the 
soap is of advantage not only while boiling, but is absolutely re¬ 
quired—for mottled soaps—when the finished soap is run into 
the frames to mottle while cooling ; the mottle is formed by the 
stearic acid soap crystallizing out of its solution in the oleic acid 
soap, and without the presence of foreign salts in proper propor¬ 
tions the soap would not possess sufficient mobility to allow of 
proper crystallization ; the mottle would be a failure. Too much 
of the foreign salts, on the other hand, gives rise to certain dis¬ 
turbances (especially in soaps not containing cocoanut oil), de¬ 
pending partly on the diminished capacity of the soap to retain 
the water in its composition, and partly on the property of these 
salts to come to the surface of the cakes of soap while drying, 
and appearing there in minute white crystals, covering the soap 
with a white film. They also attract moisture from the atmos¬ 
phere and cause the soap to “sweat” in consequence, in certain 
weather. 

In preparing lve, it is convenient and advantageous to use, 
when possible, the condensed water from the closed steam coil, 
as this water has been distilled and is consequently free from the 
lime and magnesia compounds whose presence gives rise to the 
formation of insoluble soaps, as explained in a previous chapter. 

The composition of the lye being of considerable influence 
on the properties of the soap turned out, the following general 
observations will be found useful : 

The several fats are not equally sensitive to the action of 
foreign salts in the lye ; for instance, cocoanut oil soap as has 
already been pointed out—is capable of holding a considerable 
quantity of salts and water without appearing the worse for it, 
particularly while still iresh; if a similar quantity of salt solu* 


Saving the car* 
bonate. 


Effect of foreign 
saltson thesoap 
in the frames. 


Excess of foreign 
salts. 


Different effect of 
foreign salts 
with different 
fats. 


76 


Lye. 


tion were added to tallow soap, the latter would—if not separ¬ 
ate entirely from the solution—certainly dry out very rapidly, 
become very hard and brittle, and covered with the crystals of 
the salt. In a general way, however, the following properties 
may be ascribed to the different salts and alkalies: 

Pure Caustic Soda : Tends to cause a tough consistency of 
the soap-in the kettle; a considerable excess (/. c., too strong lye) 
drives the soap out of solution. The finished soap is hard, com¬ 
paratively dry, and owing to its toughness, more likely to con¬ 
tain particles of unsaponified fac, as well as to crack on drying, 
unless the saponification has been very carefully conducted. If 
present uncombined in the finished product, the soap will be very 
hard and unfit at least for the toilet. 

Carbonate of Soda : Gives the soap greater mobility in the 
kettle, facilitates saponification if present in moderate quantity, 
and if in great excess, separates the soap from the tye. It com¬ 
bines with free fatty acids, but not with neutral fats. It present 
in the finished soap it inclines more than any other salt to come 
to.the surface of the cakes when the water dries out. Still, a 
considerable quantity of the carbonate may be incorporated into a 
soap after boiling without this latter difficulty, managing so that 
the soda crystallizes in the soap, thereby hardening it and pre¬ 
venting the carbonate from coming to the surface; this will be 
more fully described in the chapter on “Settled Rosin Soap.” 
Its presence has a less marked tendency to make the soap brittle 
than does common salt, and it is therefore sometimes employed 
together with the latter, in boiling down “ mottled ” soap. 
Crystal Carbonate is a product differing from sal soda by contain¬ 
ing only about 17% water as compared to 62% m sal soda. 

Common Salt: This, more than any other salt, renders 
water incapable of dissolving soap and is therefore used largely 
as an addition after boiling, in order to separate the soap in the 
kettle from the waste lye. The salt dissolves in the waste lye, 
and with the exception of a very small amount, settles out again. 
Common salt also makes soap more brittle by its presence than 
does any other salt. It is for this reason that some soapmakers 
prefer to use some carbonate of soda in the salt pickle for boiling 
down mottled soap. It is sometimes found among the crystals 
formed on the surface of some soap, and indeed soap containing 
common salt inclines to effloresce. In settled rosin soap especi¬ 
ally the presence of appreciable quantities of salt si disturbing, 






Lye. 


77 


and when such soap is filled with sal soda and perhaps silicate 
of soda also, cracking - and “whitewashing - ” are very apt to be 
the result. For this reason some manufacturers prefer to use 
strong lye, instead of salt, for separating soap from the waste 
lye, as traces of salt will always remain. 

Potash : The potash compounds acts similarly to the ana¬ 
logous soda combinations, but in every respect more mildly. 
Thus common salt (chloride of sodium) precipitates soap from 
its solutions, and renders it brittle, much more energetically than 
does chloride of potassium. Soap containing a proportion of potas¬ 
sium salts instead of being made with soda exclusively, is softer 
in consistency, more easily soluble in water, milder in its effects, 
dries out less, effloresces less easily, and is of a tougher*»texture 
than that containing only soda salts. In fact, the substitution 
of potash in any hard soap for a part of the soda is an improve¬ 
ment, and would probably be a universal practice but for the 
higher price of potash compounds. But in calculating the com¬ 
parative value of potash and soda for soap making, it should be 
remembered that considerable more potash than soda is required 
to saponify a given amount of fat; consequently the higher cost 
of potash is at least partly compensated for by the higher yield 
of soap caused by the presence of the increased amount of alkali. 
A quantity of fat requiring 40 lbs. of soda to form neutral soap 
will absorb 56 lbs. of potash for the same purpose, and will thus 
furnish 16 lbs. more of soap (the proportion of water present be¬ 
ing considered the same in both cases). Soap made entirely 
with potash is known as “soft soap.” A potash soap, however, 
if separated from the waste lye by means of common salt (chlo¬ 
ride of sodium), will undergo a remarkable change; it will be¬ 
come a soda soap, and the waste lye will contain chloride of po¬ 
tassium, instead of thechloride of sodium. This chemical reaction 
is only a partial one though, and a soap made in this manner still 
contains considerable (about 50%) of potash soap. At the time 
when wood ashes were almost universally used for soap making, 
the hard soaps were manufactured in just this manner, and a 
better grade of soap it would be hard to make, owing to the im¬ 
provement made in the grain, texture, etc., by the potash still 
present. (App., Note II.) A similar result is now sometimes 
obtained by using potash and soda lye together in saponifying 
fats, or—a less recommendable practice—by adding a carbonate 
of potash solution to a finished soap. When potash solution is 


Substitution o i 
potash for soda. 


More potash re¬ 
quired for sa¬ 
ponifying a 
given weight of 
fat thanasoda. 


Peculiar effect of 
salt on potash 
soap. 


78 


Lye. 


Proper strength 
of lye partly de¬ 
pends on the 
mode of apply¬ 
ing steam. 


added to soda soap, part of the latter is transformed into potash 
soap, whereby the effect of potash on a soap so treated is ex¬ 
plained. (App., Note 11.) 

The Effect of Lye of Different Strengths : As was said in the 
foregoing chapter, facts do not all require the same strength of 
lye to combine easily, but they all agree in readily taking 
stronger lye as saponification proceeds, than they will combine 
with at first. Thus tallow combines most easily at first with 
lye of not much over 10° B. in strength, if made of low grade 
caustic; but when saponification has once been induced, the 
strength of the lye can be rapidly increased up to 2(L B. and 
over. Cocoanutoil combines most readily with strong lye. The 
stronger the lye used, the less water is unnecessarily introduced 
in the kettle, and the more easily is the soap managed. Too 
weak lye, in other words too much water, is also apt to induce 
frothing, more especially with the use of open steam for boiling, 
which adds the condensing water to the boiling mass. With 
closed steam alone weaker lye must be used, of course, than when 
open steam is used also. 

Cost of Lye : Apart from their greater serviceableness for 
most purposes, the medium grades of caustic soda are also pre¬ 
ferable on account of greater economy. The low grades are 
higher in price than the medium, because of the cost of freight, 
packages and other expenses on the foreign salts contained in 
the former, which after all are lost in the spent lye. The higher 
grades are more expensive because of greater difficulties in their 
manufacture. The cheapest way to buy caustic alkaline strength 
is undoubtedly by obtaining caustic soda of about 70-72%; or the 
manufacturer may buy soda ash to advantage and causticize it 
himself, as described under “Lye Tank” in Chapter V. 

Ammonia , although in its behavior closelv allied to soda and 
potash, is incapable of saponifying a neutral fat; it can only 
form an emulsion with the latter, from which the ammonia se¬ 
parates again on resting. But free fatty acids (as red oil) can 
be saponified by crutching in ammonia; soap so formed will, on 
drying, have a consistency intermediate between potash and 
soda soaps. 



CHAPTER IV. 


Filling Materials. 


A number of substances are frequently introduced into soap 
for certain special purposes, among- which those intended pri¬ 
marily for cheapening- or “filling-” deserve separate mention. 

It may not appear rig-ht to add any such materials to soap, 
at least when the object is simply “ adulteration ” but on the 
other hand it is a fact that many manufacturers have failed in 
their attempts to create a demand for their brands of pure soap, 
which were specially made with the object to improve their pro¬ 
duct, and owing- to the demands for cheap soaps they are—much 
ag-ainst their own wishes—finding- better sales for their “ filled ” 
soaps than for the pure g-oods. Having- once been introduced, 
the manufacture of this class of g-oods is no longer a matter of 
choice on the part of the soap maker. 

Talc , also known as Soapstone, French Chalk, or Steatite. 
This material has a peculiar greasy feel, not unlike wet soap, 
whence probably the name “ Soapstone,” and is a silicate of 
magnesia (about 60 per cent silica and 30 per cent magnesia), 
with iron, lime, and other impurities mined in this country and 
also largely imported from France and Italy. It is added to some 
soaps to the extent of forty per cent (that is to say, 40 lbs. to 100 
lbs. of pure soap), but smaller quantities are generally used. It 
has no value for cleansing purposes and is added principally to 
make weight; however, in small proportion it has at least the 
advantage of making the soap mild and agreeable to the skin; 
by absorbing water it solidifies the soap, causing the latter to 
preserve its appearance and shape better on drying. It has the 
disadvantage however, of causing white soap to turn grayish on 


Pure soap not al¬ 
ways the most 
saleable. 




80 


Filling Materials. 


drying-, while colored soaps are less brilliant and clear when 
filled with talc. It is for this reason frequently used in combin¬ 
ation with silicate of soda; moreover it is a troublesome material 
if the scraps of such soaps are to be used up by remelting-. 
Furthermore, the mag-nesia in talc may be partly replaced by¬ 
lime, and this and similar variations bring- about different quali¬ 
ties which are not equally adapted for use in soaps. For cold 
made soaps the talc is generally sifted into the melted fat, or 
first well mixed with a part of the fat and then stirred into the 
bulk. To improve the texture of such soap it may be found to 
be of advantage to stir the talc into an equal weight of boiling 
2 C lye and add this (when cooled sufficiently) to the soap when 
the last lye has been added; such soap is softer at first but dries 
rapidly in its outer layers and does not soon become so very hard. 
Incidentally it may be noted here that talc is a convenient ma¬ 
terial to cover up various metal instruments, cutting wire, and 
the like, to protect them from rust or verdigris). On keeping 
talc it should be preserved from moisture, as otherwise it will 
come to contain many lumps, and will even form lumps in the 
soap though it be sifted into the fat. 

Silex, or Silica. This is a mineral which constitutes quartz 
and most varieties of sand; it is used for filling soap in the form 
of a very fine white powder. Silex has no detergent properties, 
isdnsoluble in water, and gives the soap—besides weight—a sur¬ 
face which feels somewhat rougn. In applying it, it is simply 
stirred into the soap, mixed with water. 

Silicate of Sot/a, also Water Glass, or Soluble Glass. This is 
a compound of silicic acid and soda, and is made by fusing to¬ 
gether sand and alkali. It is in the market in the form of a dry 
powder, but more ordinarily as a thick, syrupy solution. Of it¬ 
self it is really colorless, but from the process of manufacture 
there frequently remains some foreign matter which gives it a 
yellowish tint. Its use is greatly to be preferred to silex, for 
silicate of soda has some detergent property of its oAn, owing 
to the alkali in its composition; besides it renders some hard 
water softer, thereby avoiding waste of soap. Silicate of soda 
is made in several forms and of various degrees of concentration 
(measured by the hydrometer) and may be easily diluted with 
water. It is generally used at a strength of about 40° B., but 
varies somewhat in composition, containing more or less alkali 
in excess. If weak in alkali it is sometimes necessary to add a 


Filling Materials. 


81 


pound of 38° lye for every 5 lbs. of silicate used in the soap, in 
order to prevent the silicic acid from crystallizing- out. Fresh 
soap filled with silicate has a better appearance than one filled 
with talc, but on drying- it becomes harder, lathers less, and- is 
sharper on the skin. Cold-made soaps containing- silicate are 
apt to have soft, spongy parts or even free fat collect in the cen¬ 
ter if run into larg-e frames, especially so if an excess of lye is 
not used, or when the proportion of silicate added is small; such 
soaps are therefore best run into small frames. Silicate of soda 
is frequently used tog-ether with talc. 

Silicate of potash is a similar article, and sometimes em¬ 
ployed for filling- soft soaps. Being- made with the more ex¬ 
pensive potash, it is naturally more expensive than is silicate of 
soda. 

The form of silicate of soda most commonly employed by 
soap makers is known as “N” silicate, which has a strength of 
39—40° B. and is sold ready to be used just as it comes from the 
barrel. For cold-made and half-boiled soap almost any desired 
amount may be added, from 30 to 50 lbs. to 100 lbs. of fat being 
a common proportion. In settled rosin soaps from 5 to 10 per 
cent, of the weight of soap is most generally used, together with 
a like amount of carbonate of soda solution. “ K ” silicate is a 
similar preparation, somewhat milder and thinner than the“ N” 
(36° B.) and also ready for use as it comes. “ S ” silicate is an 
old fashioned form, of the consistency of a jelly, but chemically 
similar to the grade “K” It requires melting by open steam 
and is but little used by the soap makers at present. 

Starch is sometimes used in soap, but more for the purpose 
of binding the materials together than as an adulteration. By 
stirring starch into, say, like proportions of sal soda solution and 
silicate of soda, and boiling on open steam (in a closely covered 
kettle, to prevent it from jumping out) a thick mass is obtained 
which may be used in almost any proportion desired. By boil¬ 
ing in this manner, the starch absorbs much water and the filling 
is in every way more desirable than if the starch were used 
without having been boiled previously. Starch and flour, how¬ 
ever, have this disadvantage that in the course of time, say a 
few months, they undergo decomposition, giving rise to a bad 
odor, and in severe cases even to fungoid growths on the surface 
of the soap. In cold soap also starch may be used by mixing it 


Varieties of sili¬ 
cate. 


Preparing starch 
for filling. 


82 


Filling Materials. 


well with the melted stock before running- in the lye; for the 
purpose of thoroug-h mixing- the starch must be dry. 

Mineral Soap Stock , a by-product obtained in petroleum refin¬ 
ing-, is used to a considerable extent in filling- soaps. It is in¬ 
soluble in water and has no deterg-ent properties. Being- a min¬ 
eral product, it cannot be saponified. 

sai soda not an Soda Ash, Sal Soda (Washing- Soda) is not, strictly speaking-, 
aduiteiation. a mere cheapening- ingredient, for it hardens the soap in which 

it is introduced, contributing to economy in its use and adding 
to its cleansing power. The use of this material is fully de¬ 
scribed in Chapter VII. For laundry soap this is undoubtedly 
the best filling material known, so far as the qualtity of the pro¬ 
duct is concerned. In washing with hard water the sal soda is 
quicker to act on the lime salts contained therein; it neutralizes 
them, and thereby saves much soap from being decomposed and 
wasted. . 

Sulphate of Soda (Glauber’s Salt) has a similar effect as sal 
soda on the hardness of the soap, but it is different in that it has 
no washing power, does not neutralize the salts of hard -water, 
and that it is less liable to effloresce. 

Common Salt hardens soap made largely of cocoanut oil and 
containing much water. It is not used very much as a filling in 
this country, however, but is quite common in cheap grades of 
cocoanut oil soaps made in Europe. 

Carbonate of Potash (Pearl Ash) dissolved in water is used in 
some soaps as a filling material, softening the soap, improving 
its texture and lathering property, and making it somewhat 
transparent. (Its tendency to soften the soap mav be counter¬ 
acted by the additional use of salt water , which is also used as a 
filling in some soaps containing much cocoanut oil.) It absorbs 
moisture, however, from the atmosphere in damp weather and 
spoils the wrappers thereby. 

Borax is a useful addition, especially in laundry soaps, as it 
renders fabrics very white without affecting their fibres or deli¬ 
cate colors. It is a white, mildly alkaline mineral, which ren¬ 
ders the soap more effective without attacking the skin in wash¬ 
ing. In laundries it is used extensively in place of the sharper 
soda. 

***** 

The above-mentioned substances are those most ordinarily 


Fiujng Materials. 


83 


used, either for filling- or for increasing- the deterg-ent power of 
soap. To this list may be further added : Sugar, Glycerin, and 
Alcohol for transparent soaps ; Vaseline (also Glycerin), and 
Wax, for emolliency ; Sand, Pumice Stone, Tripoli, etc., for scour¬ 
ing- soaps; Sulphur, Tar, etc., for medicated soap; Ammonia, Ox¬ 
gall, Benzin, etc., for removing- spots from clothes; and a long* list 
of substances, such as china clay, flour, dextrine, bran, oatmeal, etc., 
which are added either as a simple adulteration, or for their 
(mostly imag-inary) beneficial effect in certain cases. 

Formulas for using- mixtures of these various fillers will be 
found on other pag-es, in connection with the description of 
various soaps. 


VARIOUS OTHER MATERIALS. 

Alum: This substance is mentioned in several places in 
this book in connection with the purification of fats. It is a 
sulphate of alumina and potassium and its effect is to combine 
with impurities of the nature of g-lue and to precipitate them. 

Infusorial Earth : This substance, as it comes from the 
mines, contains from 75-82% of silica, and more or less of alu¬ 
mina, iron compounds, org-anic matter, and moisture. It is 
cleaned, ground, dried and sifted for use in scouring- soaps. It 
is the same substance which is so often spoken of in connection 
with nitro-g-lycerine in the manufacture of dynamite. 

Tripoli is a diatomaceous earth, or in other words it is a de¬ 
posit of the siliceous envelopes of fossil diatoms and consists 
chiefly of very finely divided silica. It is used principally, so far 
as soaps are concerned, in scouring- soaps. 

Fuller's Earth : This is a kind of bluish-gray to yellowish- 
green clay noted for its usefulness in the process of fulling cloth in 
which it is valuable by its absorption of oil and grease; for this 
purpose it is now largely superseded by soap, but has come into 
extensive use in its turn in the treatment of oils and fats, as 
hereafter noted, before these are made into soap, etc. Fuller’s 
earth is found in Florida, New York, South Dakota, and several 
other states, and large quantities are imported from Europe. It 
is claimed that the English earth is superior for deodorizing 
fats, but that for decolorizing the American product is more ef¬ 
fective. The clay is used after grinding it to 120 mesh or finer, 
crutched into the hot oil and removed again by a filter press 


84 


Filling Materials. 


which takes out the coloring - impurities which adhere to the 
earth. The action of this material is mechanical rather than 
chemical, and is best obtained when the clay contains the least 
possible amount of moisture. The composition of various kinds 
varies, being - approximately: Silicic acid 50% to 60%; alumina 
15 to 30%; iron oxide 3 to 5%; quartz 10 to 13%; moisture 9 to 
18%; with small amounts of lime, magnesia, etc. To examine 
a lot of this material for its quality, the easiest and most reliable 
method is to make a small trial test. Sometimes it happens 
that a stock is bleached with this material and looks very white, 
but the soap made from it by boiling is as dark as if unbleached 
stock had been used; the true explanation of this is doubtful, 
but in view of the iron oxide contained in Fuller’s earth it is 
possible that free fatty acids in the stock give rise to iron soap 
which contaminates the product. A preliminary removal of 
these fatty acids by bleaching with lye, as described under “tal¬ 
low,” will largely remedy this. Heating the Fuller’s earth be¬ 
fore use, to drive off moisture, increases its effect. 

Alcohol : Alcohol is used in the soap factory for a variety 
of purposes. The officinal alcohol of the U. S. Pharmacopoeia 
contains in 100 parts 94 volumes of absolute alcohol, (this being 
equal to 91% of alcohol by weight.) 

To reduce an alcohol of given percentage to a lesser one 
when the percentage is reckoned by volume , the following rule 
has been given by Dr. W. H. Pile. 

Multiply the quantity of the alcohol (either in fluid ounces 
or in gallons) by the percentage strength and divide by the re¬ 
quired percentage; the quotient gives the quantity to which the 
alcohol must be diluted by the addition of sufficient water. 

The same author gives the following : To make a definite 
quantity of any desired strength from a stronger alcohol: Mul¬ 
tiply the required amount by the required percentage and divide 
by the percentage of the given alcohol; the quotient gives the 
quantity to which the alcohol must be made up by the addition 
of water. 

It will be noticed that the quantity of water is not definitely 
stated in either case; to do so would necessitate impracticable 
calculation for the contraction in volume which occurs on mix¬ 
ing alcohol and water. 

Proof spirit contains 52)4 per cent, by volume of pure alco¬ 
hol and is a mixture of 49 parts by weight of pure alcohol with 




Filling Materials. 


85 


51 parts water. This is the strength of the proof spirit usually 
employed, but by law proof spirit is equal parts by volume of 
absolute alcohol and distilled water, having a specific gravity of 
.9 j> 3. The Internal Revenue Law of the United States provides 
that proof spirit shall consist of a mixture of equal volumes of 
water and alcohol, the latter having a specific gravity of “seven 
thousand nine hundred and thirty-nine tens of thousands at 60 c 
F., ’ water at its maximum density being taken as the unit. 
This alcoholic liquor will have a specific gravity of 93,353 at 
60° F., water at its maximum density being taken as the unit, 
and will contain by weight 42*7 per cent, of absolute alcohol. 
A gallon of this spirit weighs 7*77 pounds; 42*7 per cent, of 7*77 
pounds is 3*31 pounds. Thus we see that a gallon of proof spirit 
in the United States contains 3*31 pounds of absolute alcohol. 

Dilute alcohol (U. S. Ph.) consists of equal measures of 
officinal alcohol and water; it contains 39 per cent by weight, or 
46.33 per cent by volume, of pure or absolute alcohol, and has a 
specific gravity of .941, equal to 19 of Baume’s light hydrometer. 

Water: Water freezes at 30° F., and boils at 212° F., un¬ 
der ordinary atmospheric pressure. Owing to its peculiar prop¬ 
erty of expanding in the act of freezing, tanks and pipes fre¬ 
quently become leaky in very cold weather. Another notable 
property of water is its very great power of dissolving the most 
varied substances, to which circumstance is due its varying 
quality, for obviously the opportunity of thus becoming charged 
with various salts, gases, organic impurities, etc., is very differ¬ 
ent in the cases of spring, river and lake, or rain water. Water 
rich in dissolved carbonate and sulphate of lime and magnesia is 
known as hard water and these salts may be present in it to the 
extent of 1 %\ they interfere with the solubility of soap in the 
water and have various effects of practical importance which 
will be noted in the following pages as occasion demands. On 
boiling hard water carbonate and sulphate of lime are precipi¬ 
tated and in the boiler give rise to “scale.” (See App. 
Note 10.) 

Li??ie : In burning carbonate of lime (chalk, oyster shells, 
etc.,) the carbonic acid escapes and there remains calcium oxide 
or burnt lime; if water be now added to the latter the hydrate 
is formed. (See App. Note 18.) The caustic lime is used to 
abstract carbonic acid from soda ash, in other words to causticize 
soda, a process described in detail on another page. As burnt 


86 


Filling Materials. 


lime has the same tendency to absorb water and carbonic acid 
from the air (and to become more or less ineffective thereby,) it 
is necessary to either use it fresh or to protect it from such ab¬ 
sorption. 

Salt : Ordinary salt (sodium chloride,) is very largely in 
use in the soap factory—to say nothing- of the fact that the soda 
of commerce is made from it. It is very soluble in water, but 
almost insoluble in pure alcohol. As the commercial article is 
practically always satisfactory, there is no need to go into 
further details in this place. 


CHAPTER V. 


The Soap Factory. 


LOCATION. 

In deciding- to establish a soap factory anywhere, it is taken 
for granted that due attention has already been paid to such ques¬ 
tions as the cheap supply of fuel, sufficient and suitable water, 
the facilities for obtaining tallow, &c., at the lowest rates, and 
shipping facilities for the finished products on the other hand; 
so we may pass these over now with merely mentioning them. 

ARRANGEMENT. 

The conditions determining the internal arrangements of a 
soap factory are so variable, that it is very little to the purpose, 
practically, to attempt the description of any one well arranged 
establishment of this kind. The quantities and varieties of soap 
turned out, the raw materials used, and the machine^ available 
for the pnrpose, as well as the facilities of thebuilding in which 
the factory is located, all have their peculiar bearing on the pro¬ 
per arrangement and equipment of the works. However, the 
avoidance of all unnecessary work being demanded alike by con¬ 
venience and economy, a good rule which has been found to ap¬ 
ply under almost all circumstances, is to elevate the raw mate¬ 
rials at an early period to the upper floors of the factory, so that 
in the successive stages of manufacture they may descend by 
means of their own gravity to the lowest floor, whence the soap 
proceeds in the course of cutting, drying, pressing and packing, 
to the last (shipping) room of the factory, thus obviating as far 
as possible all pumping or repeated lifting on the elevator, the 
goods passing in natural order from one machine to the next, 


General rules gor* 
erning arrange¬ 
ment of factory. 




88 


The Soap Factory. 


without covering- the same ground repeatedly. In building's oc¬ 
cupying- only little ground, so that there is not room on the low¬ 
er floor for the operations of cutting-, etc., mentioned, the frames 
of soap are g-enerally broug-ht to a higher stor} 7 by the elevator 
and there cut, pressed and packed, and brought into the shipping 
room by means of the elevator or a chute. In large factories it 
is moreover found to be most economical to have separate engines 
in the several parts of the building where steam power is used, 
to obviate the use of much shafting and belting. Another point 
requiring attention is an economical arrangement by which raw 
materials and fuel can be easily brought to their proper place in 
the factory without unnecessary handling. 

Further than this there is probably no general suggestion 
regarding arrangement that can be made, which will hold good 
in all cases. We will therefore, after a few words regarding the 
building, proceed to a description of the machinery placed in the 
factory, leaving the arrangement to the judgment of the practi¬ 
cal soapmaker, who will suit his particular circumstances. 

THE BUILDING 

is in many cases one originally designed for another purpose 
than to serve as a soap factory, or it may have been erected be¬ 
fore a practical soap maker was consulted, or the growth of a 
business already established require additions which complicate 
the problem, so that it is often necessary to adapt the arrange¬ 
ment of the machinery to the conditions alread} T existing. This 
is obviously less rational than to construct or select the building 
in accordance with the necessary machinery, &c. 

The very first requirement should be that the building be 
amply able to carry the often enormous weights concentrated in 
the upper stories, as water tanks, lye tanks, kettles, &c. This 
should be too self-evident to require mention, but several very 
serious and even fatal accidents that have followed imperfections 
in this respect amply justify this remark. 

For a medium-sized factory the building should have at least 
two stories, or a story and basement, though a 3-or 4-story build¬ 
ing is the most convenient and practical, being preferable to a 
low building occupying a larger floor space. In any case the 
boiling is carried on in the upper story, the kettle passing through 
the floor into the story below, and the crutcher is placed on the 
same'^floor in such a manner that the soap can be taken out into 





The Soap Factory. 


89 


the frames on the floor below; the boiling- floor; this arrangement 
enables the soap maker to keep watch of the kettle and of the 
crutcher, sal soda tank, &c., at the same time. The cutting, 
drying, pressing and wrapping may then be carried out on the 
next lower floor. The elevator should go up above the main roof 
and connect with a small shed above the roof, so placed as to 
facilitate bringing the rosin into the kettle by way of a chute. 
One such chute can be made to supply two kettles, by suspend¬ 
ing it from the middle and shifting its direction as needed by 
means of ropes at each end, running over pulleys connected with 
the ceiling. 

To each end of the floor of the chute is bolted a flat trian¬ 
gular piece of hard wood, to assist in spreading the rosin over the 
surface of the kettle. It may also be convenient to have a 
chute leading from the shed on the roof down to the fireroom, so 
that rosin staves can be dropped down without further handling. 

Tallow and oils, when steamed out, being best run into a 
settling tank (described further on), the latter—in low build¬ 
ings—is usually not advantageously placed when the top is even 
with the basement floor, and so that the melted stock runs direct¬ 
ly down into it, or the settling tank is on the basement floor and 
the steaming out is done on the first floor. In high buildings it 
may be preferable to steam out the stock on the top floor. 

THE LYE TANK. 

The size and number of lye tanks used must be adapted, of 
course to the requirements of the factory, as is also the manner 
of making the lye. It is usually best to have separate lye tanks 
for lye that is to be used in cold made and transparent soaps, as 
pure alkali, a different degree of strength, and perhaps the addi¬ 
tion of potash, are needed in this lye, so that it must be kept 
apart from the lye for the boiled soaps. 

The tanks are generally made cylindrical, and sometimes 
rectangular, of about % in. sheet iron, or sheet steel, and in most 
cases have a discharge pipe near the bottom, through which the 
lye runs off by its own gravity when the discharge cock is open¬ 
ed; this pipe is best arranged with a slight upward inclination, 
so that dirt cannot too easily run out, and is preferably 2 or 3 
inches from the bottom; at the middle of the bottom is then 
placed a valve for washing out the sediment which collects from 
time to time. A steam pipe is also provided to introduce steam 


90 


The Soap Factory. 


for heating*, to dissolve the alkali, or when it is found desirable 
to accelerate the solution of the caustic in the water, (although 
with proper manipulation this aid is not really required, except 
to save time when in a hurry, or when poor grades of alkali are 
to be dissolved); ordinarily—with good grades of caustic—the 
heat which is developed spontaneously by the process of dissolv¬ 
ing the caustic is sufficient, if rightly managed. The tank should 
be large enough in diameter to admit one or more drums 
of alkali when placed in it crosswise. Such simple tanks as de¬ 
scribed are most ordinarily used for making the lye, the caustic 
being simply placed on the bottom and sufficient water run in to 
make lye of the desired strength. In some factories the drums 



Hg. o. 


are pounded with heavy hammers, to break up the caustic 
which is then thrown into the tanks, to be dissolved with the aid 
of steam. 

In some factories the iron drum is removed without break¬ 
ing up the caustic, and the latter is placed in solid blocks on the 
bottom of the tank as before mentioned; on running in water, if 
high-grade caustic is used, the latter dissolves without the aid of 
steam, and the lye near the bottom is very strong, becoming 
gradually weaker towards the top. By using a swing-joint pipe 
for drawing off the lye—similar to the pipe used for drawing the 
soap from the kettles—lye of different strength may be drawn 
from the same tank, by simply raising or lowering the inlet of 
this pipe. (See Figure 5.) Where smaller quantities of lye are 
made at one time the following plan may be found very con¬ 
venient: 

The drum, after removing only the heads, is suspended above 
the lye tank by an overhead differential pulley block, (Moore’s 




















































































































































The Soap Factory. 


91 


patent and others), and lowered until it is just covered by the 
water contained in the tank. As fast as the lye forms it sinks 
t° th e bottom, forcing the fresh water up; the heat developed 
spontaneously aids in the solution, and as water or weak lye con- 



Fig. 6. 


tinues to be displaced by the stronger lye and to rise to the top, 
the caustic is soon dissolved. By making the lye in this man¬ 
ner, mechanical agitation, breaking up the caustic, and also the 
use of steam, are avoided, and the very little extra time required 
may be saved, if necessary, by using an extra tank at the same 



Fig. 7. 


time, or one large enough to admit a sufficient number of drums 
at a time. (See Fig. 6.) 

Instead of suspending the drums by a chain, a false bottom 





































































































































































































































































































































































92 


The Soap Factory. 


or grate may be placed in the tank for the drums to rest on, or 
supports ma} 7 be laid across the sides of the tank on which the 
caustic is rolled, after removing- the iron drum. These supports 
may be connected by perforated sheet iron to prevent larg-e lumps 
of caustic falling- in while melting-. When this arrangement is 
used it is convenient to have the top of the tank even with the 
floor to facilitate rolling- on the caustic. (See Fig - . 7.) 

This arrangement, although exceedingly convenient, is not 
used SO'much as it deserves to be; in most factories the caustic is 
broken up by pounding the drum, and placed on the bottom of 



Fig. 8. 


the tank; water is then run in, and open steam introduced to ag¬ 
itate and rapidly heat the mass. 

In place of using steam to assist in dissolving caustic, the 
use of an air pump has been suggested, especially when there is 
use for such a machine for other purposes also. The advantage 
of this is—apart from greater safety—that the lye becomes less 
heated, which may be desirable at times, as when the lye is to be 
siphoned up to the storage tank. But, unless their is hurry, 
neither this nor steam will be required if the tank is properly 
arranged. 

Still another arrangement, which is not much used however, 




























































































































The Soap Factory. 


93 


consists of an ordinary tank into which a smaller perforated 
cylinder, or a wire netting-, has been set. The caustic is placed 
between the two cylinders and water admitted into the tank. A 
mechanical ag-itator which reaches into the water is then set in 
motion until all the caustic is dissolved. The object of the 
inner cylinder is to keep the lumps of caustic from interfering 
with the ag-itator blades. (See Fig-. 8.) 

If the lye made is to be used for cold-process soap, it may at 
times be necessary to have some provision made for cooling- it off 
rapidly, in order to save time. For this purpose a coil of pipe 



may be set into the tank, through which cold water may be cir¬ 
culated after all the caustic has been dissolved. When possible, 
however, it is much better to let the lye for cold made soap cool 
off slowly, so that the dirt settling to the bottom, and that ris¬ 
ing in the form of a scum, may be separated from it before use. 

Lye for the cold process requiring to be very caustic, it is 
also necessary to prevent it from absorbing carbonic acid from 
the atmosphere; to this end different devices are adopted. Prob¬ 
ably the simplest, and at the same time most effective method, 
is to place in the tank a quantity of mineral soap stock which 
will, as it does not saponify, always float on the surface of the 
ye and thus effectually exclude the air. Others cover the tank 


Cooling lye rapid, 
ly,for cold pro¬ 
cess. 


Settling lye. 


Means of preserv¬ 
ing lye for cold 
process. 









































































































































































































































































































94 


The Soap Factory. 


Water connection 
with lye tank. 


as nearly air tight as possible, and perhaps place some quicklime 
on the top to absorb the carbonic acid from the surrounding 
atmosphere. This is objectionable, however, as it is rather in¬ 
efficient, and there is always the danger of some of the lime 
falling accidentally into the lye. 

A convenient arrangement on a l} r e tank is also a water pipe 
connected with the discharge pipe, as in the engraving, Fig. 9. 
Its object is to permit drawing off either water or lye, or both 
together, at pleasure, so that the pipe leading to the kettle will 
carry any desired strength of lye, from the strong lye in the 
tank down to simple water, according to how far the different 
valves are opened. 




The lye pipe might be given a short upward bend on issuing 
from the tank, which will have a tendency to prevent foreign 
matters, which have settled to the bottom, from going out. 

Although the lye tank should be placed higher than the 
kettle, so that the lye may run out of its own accord into the 
latter, circumstances at times require that the lye be raised to a 
higher level. For this purpose a cast iron steam-syphon or 
“ejector” is adapted, which works on the principle as herewith 
illustrated, and which by the injection of a current of steam 







































The Soap Factory. 


95 


through the tapering tube creates a vacuum that forces the lye 
to rise into the hollow globe and then forces it upward through 
the outlet. With a steam pressure of 60 lbs. it will lift liquids 
25 feet and elevate them about 15 feet above the ejector. Appar¬ 
atus of this kind are made by A. W. Cadman & Co., Hersey Mfg. 
Co., and others. Less convenient usuallv, but worth mention- 
ing, is the use for this purpose of an apparatus made on the plan 
of the stock blower to be described in the following pages. 

The outlet pipe from the lye tank to the kettle is sometimes 
made to terminate in a perforated piece, in such a manner that 
through the perforations the lye is distributed evenly over the 
kettle. 

Flanges, patches, and the like, are riveted on, but not bolted, 
as warm lye is apt to destroy such patching, as well as lead, tin, 
and the like, for which reason soldered utensils and lead pipe 
soon become leaky when used for lye. 

STRUNZ PATENT LYE APPARATUS. 

The manufacture in the soap factory, of caustic lye from 
soda ash by treatment with lime, was the universal practice be¬ 
fore caustic soda became an article of commerce; but the crude 
appliances used for the purpose were so inconvenient, that in 
course of time commercial caustic soda came into general use in 
this country. In the meantime, however, improvements have 
also been made in the apparatus and methods by which soda ash 
is made caustic by the soap maker, especially during the past 
several years. A number of very essential improvements have 
been made in this apparatus with the result of further simplify¬ 
ing the process to such an extent that the preparation of caustic 
lye from soda ash has become profitable even at a comparatively 
small difference between the price of soda ash and commercial 
caustic. The labor and other expense items, as well as the 
proportion of lime required having been reduced to a minimum. 

The accompanying illustration shows a L} T e Plant supplied 
with all the latest improvements. This plant has a capacity 
equivalent to 8 drums of 76% caustic per day. Although the 
profit on such a plant increases somewhat with the capacity, 
this process is profitable in cases even where the consumption of 
caustic lye does not exceed an equivalent of 150 drums per year. 

By this method the entire process is completed in a single 
operation with the least possible amount of lime; giving a yield 


96 


The Soap Factory. 


which is practically perfect. There is no driving-machinery to 
operate—no vacuum pumps and no air pumps to look after—in 
fact no other power is applied than that produced by direct steam 
from the boiler entering the apparatus. The proportion of lime 
required varies not only according to its purity but is also effected 
by the manner in which the process is conducted. The amount 
of lime now required for causticizing is much less than formerly. 
Exceptionally good grades now giving a satisfactory result in 
the proportion of from 63 to 65 lbs. of lime per 100 lbs. of soda 
ash. The lime must be well burned and as free from contamin¬ 
ation by magnesia as possible. 



In the apparatus illustrated on page 97 made by F. B. 
Strunz, Pittsburgh, Pa., the lye adhering to the lime-waste is 
practically all saved. The lime-waste is usually mixed with 
water and flushed away into the sewer. Attempts have been 
made to recausticize this lime-waste but the operation proved 
too expensive and could not compete with fresh lime which can 
be procured in most localities at $4.00 to $5.50 per ton. How¬ 
ever, where it is produced in sufficiently large quantities this 
lime waste would furnish excellent material for manufacturing 


































The Soap Factory 


97 


Portland cement. For this purpose the lime-waste requires no 
preliminary treatment. In some cases this material can undoubt¬ 
edly be turned to value. 

Regarding - the cost of lye made by this process as compared costofiye. 
with that made by dissolving caustic soda, Mr. Strunz furnished 
in the American Soap Journal the following figures, which may be 
readily changed to suit different localities, etc.: 

“In Pittsburgh the saving amounts to about 1 ]/i cents per 
pound, figuring Pure Alkali at $1.42^2 for 48%: Caustic Soda 


Fig. 11 







W/A/tt 


HEIN STRUNI'S - 

C O O ft O CO 

LYE APPARATUS 


*l*-&nAGOO/V Purs 




lim., liiH 

1 m’s/;/»r-/wAvizz 

ill- 

1 ./I l| 

7 rnmim 

Wfi 




\ 14'JcjV 

QsT 11 


77% at $3.08 for 60%, and freight on each at 15 cents per cwt. 
from New York. Lime is worth 20 cents per cwt., f.o.b. Pitts¬ 
burgh. 

600 lbs. Caustic, 77%, at $3.08 for 60%.$23 72 

Freight on 600 lbs. Caustic from New York to Pittsburgh 90 

Labor, dissolving Caustic. ^ 


$24 77 




























































































































































98 


The Soap Factory. 


“Caustic Lye Solution, equivalent to 600 lbs. Caustic 
Soda of 76%, is produced by: 

800lbs. Soda Ash, 58%, $1.42)4 for 48% (at $1.72) .$13 76 
Freight on 800 lbs. from New York to Pittsburgh, 

at 15 cents per cwt. 1 20 

650 lbs. Lime, 20 cents per cwt. 1 30 

Labor, preparing soda ash solution and adding 

Lime, 1)4 hours.23 cents 

Labor, removing lime waste from lve apparatus, 

1 hour.15 cents 38—$16 64 


Saving on 600 lbs. Caustic, 77%. $ 8 13 

or, $1.35)4 per cwt. 

“In the East, where oyster shell lime can be procured at 13 
cents per cwt., and on account of a slightly greater difference 
between the f.o.b. prices of Caustic and Soda Ash, the saving is 
somewhat more: Figuring $1.48 per cwt. of 77% Caustic, or 
very nearly 1 )4 cents per pound.” 

Under date of May 24, 1898, F. B. Strunz patented a kettle 
of special shape and with a particular arrangement of steam 
pipes and means for supplying the lime; the kettle and the 
apparatus described in the foregoing forming together a lye plant 


THE MELTING TROUGH. 

In smaller factories the tallow and other stock are often 
simply dug out of the barrels and placed in the kettle to melt. 
This entails more or less damage to the packages and consider¬ 
able work, for which reasons the melting of the stock by steam 
introduced into the barrels is much to be preferred. Melting has 
the further advantage of removing the fat more fully, an item 
which amounts to more than one might think, for in one case 
where the difference was investigated fully and systematically, 
it was found that a certain barrel filled with palm oil weighed 
230 lbs. after all the stock had been carefully scraped out; on re¬ 
filling and later melting out the stock it weighed only 206 lbs. 
The 24 lbs. gained were oil that had soaked into the wood. A 
trough is used for this purpose, upon which the barrels are placed, 
and which receives the melted stock; it is made of sheet-iron or 
sheet steel, rectangular in form, and need not be more than about 
five inches high; it should incline slightly toward the outlet 









The Soap Factory. 


99 


above the settling- tank. The barrels are placed across the 
trough, or on timbers laid across the end pieces of the latter, 
with their open bung-holes downward. Pipes of ^-inch diame¬ 
ter are so arranged that steam can be turned into the barrels 
through the bungholes, either by having a separate pipe for each 
barrel, as shown in the accompanying engraving, or by a main 
pipe along the bottom of the trough, from which branches reach 
upward into the hogsheads or barrels, as indicated by the dotted 
lines in the same engraving just referred to. The ends of these 
branch pipes have an elbow joint, which turns easily, so that it 
may be introduced into the bunghole after the package has been 
properly placed. 

By admitting steam through the pipes the contents of the 
hogsheads are quickly emptied and can be run to the kettle or 
settling tank while still hot, thus saving most of the heat ex- 



Fig . 12. 


pended on the operation. A fine wire sieve should be placed in 
the trough where the discharge pipe is connected, so as to arrest 
chips of wood and coarse dirt, that would otherwise go into the 
kettle. 

Instead of a trough, a simple rack may be used to support 
the barrels for melting the stock. 

A convenient tool in this connection is a piece of board, two 
inches wide, and long enough to reach across the two pieces of 
timber that are placed lengthwise over the trough. Through 
this board, near one edge, are driven four or five very heavy 
nails, and the board is then nailed upon another, so as to prevent 
the nails from being pressed back again. These are used as 
blocking for the barrels, to prevent tipping over. , 

THE SETTLING TANK. 

From the melting apparatus the stock should be run to a set- 


o\ 

% 

i >>> 

* :> > > 


\ 





































100 


The Soap Factory. 


tling tank, so that it may be properly settled and alsoexamined, 
instead of running- it directly into the kettle. These settling- 
tanks should be arranged with marks indicating- their capacity, 
so that the amount of stock placed in them or withdrawn from 
them may always be approximately calculated. ' In consideration 
of their great weig-ht, temperature, and conveniences, these tanks 
are frequently placed in the basement. 

THE STOCK BLOWER. 

Unless the melting- trough (or the settling tank) is so placed 
that the melted stock runs to the kettles by its own gravity, 



Fig. 13. 


some provision for conveying it there is required. This may be 
done by a pump or by a blower. The pump will be described 
hereafter. 

The stock blower, which is used in some factories for con¬ 
veying the fats from the settling tanks to the kettles, consists of 
a sheet-iron tank provided with a tight-fitting cover, and is test- 
ted for a pressure of at least 80 lbs. to the square inch. It has a 













































































































The Soap Factory. 


101 


1% inch pipe (A) reaching' nearly to the bottom of the tank, for 
carrying- off the stock. B is a pipe for admitting- steam, the pres¬ 
sure of which forces the stock out of the tank. D is a pipe 
throug-h which the steam escapes from the empty blower when 
fresh stock runs in. E is a pipe from the stock tank. C is a 
valve throug-h which accumulated dirt may be blown out. A 
steam pipe should also be connected with pipe A for blowing- 
back, to clear it in case it becomes clog-g-ed by fat that may have 
become chilled. This apparatus may be improved for some uses 
by inserting- a dished false bottom (see small engraving-), with a 
hole in the centre. The dirt and water settling out from the 
stock (which may be kept warm by waste steam) would find its 
way below the false bottom and be prevented by the latter from 
going along with the stock on emptying the tank underpressure. 

An apparatus of this description may, under certain condi¬ 
tions, be of use to convey fluids other than fats, as for instance 
lye. 

THE SOAP KETTLE. 

In regard to soap kettles there are a great many variations, 
not alone in the actual requirements, but also in the opinions pre¬ 
vailing among practical soap boilers. 

In Europe the kettles or “pans” are still in many instances 
heated by fire, while the contents are stirred by hand, but this 
feature has been superseded in this country many years ago by 
the use of steam; it is therefore not necessary here to point out 
the many advantages which steam kettles have over the old-fash¬ 
ioned fire-heated affairs. Suffice it to say that the object of ap¬ 
plying heat to the ingredients in the soap kettle is twofold, name¬ 
ly not only to raise the fat and lye to a temperature favorable to 
the chemical reaction but also to produce the movement of the 
contents which, by thoroughly mixing them, contributes very 
largely to the process of saponification; it is hardly necessary to 
point out how much in this respect the introduction of open steam 
is superior to a fire heated kettle. Indeed, as shown in the cold 
process, a temperature far below boiling is sufficient to induce 
saponification, and with the use of open steam the reaction be¬ 
gins much earlier, as a result of the mechanical action of the 
steam, and at a comparatively low temperature. 

As to size, soap kettles range from a capacity of a few thou¬ 
sand pounds to those holding 150,000 lbs. of finished soap, and 


All kettles heated! 
by steam. 


Size of kettles. 


102 


The Soap Factory. 


more; the largest kettles still practical to use hold not much over 
250,000 lbs. In shape the cylindrical form is the most common, 
square kettles being comparatively rare as they are in several re¬ 
spects inconvenient to use. As to dimensions, the proportion 
best adapted for good boiling is approximately 2 feet average 
width to 2/4 or 3 feet depth. Too deep a kettle in proportion to 
width is liable to cause boiling over and “jumping.” The walls 
of the kettles are either perpendicular or taper towards the 
bottom. 

A kettle of the latter kind, and the connections required for 
practical working, are illustrated by the accompanying Fig. 15, 
which represents one of the kettles used in the factor} 7 of Messrs. 
A. Melzer & Co., of Evansville, Ind., as described by them in 
the American Soap Journal , as follows: 

“The dimensions of this kettle are: Depth 15 feet; diameter 
across top, 15 feet; diameter across bottom, 10 feet; capacity, 60,- 
000 pounds Settled Soap. Bottom of kettle is made of % inch 
flange iron dished 12 inches. The first 4 feet of sides of kettle 
are made of % inch iron, the balance 3-16 inch; seams vertical. 



Fig. 14. 

To center of bottom is riveted a heavy cast-iron pouch (Fig. 14), 
tapped for two 2)4-inch pipes, one for running out the spent lye, 
and the other, which is at right angels to the first, for running 
out the nigre into a receptacle for that purpose, preparatory to 
pumping it into other kettles. This latter pipe may be connect¬ 
ed direct with a rotary pump, but in this case there would be 
liability of sand and nails getting into the pump, which might 
cause much trouble. Both these discharge pipes are supplied 
with a half-inch steam pipe for clearing them of cold soap, sticks 
and other obstructions that may have lodged therein. The steam 



Fig. 15.—SOAP KETTLE. (See page 102.) 




















































































































































































































































































































































































































































































































THE NEW FRENCH SYSTEM OF MILLING. 


(See pages 169 and 17U.) 
























































































































































The Soap Factory. 


103 


pipes that feed the coils in the kettles enter through cast-iron 
flanges and an extra 34 inch wrought plate riveted on side of the 
kettle just above the bottom. Each kettle is supplied with a gen¬ 
eral steam valve, which shuts off the steam on all the coils; a 
valve for each, the open and closed coils, and a small valve or pet 
cock for draining the pipes and to let escape freely any steam 
which may pass the main valve, and thus prevent any possibility 
of it getting into the kettle at a time when it is not wanted there. 
These valves can all be operated by means of iron rods conveni¬ 
ently located at the kettles in the boiling room. The pouch on 
bottom of the kettle is covered over by a grating made of % inch 
wire and having 34 inch meshes for the purpose of preventing 
bungs or tools that may have found their way into the kettle 
from obstructing the discharge pipes. The open steam coil is a 
single 36 inch ring, made of extra strong 1% inch pipe and per¬ 
forated with a sufficient number of inch holes. The closed 
steam coil is a flat spiral, containing 350 feet of continuous 1% 
inch extra strong pipe. This form of coils we have found the 
most practical, after trying a variety. 

“The finished soap is discharged through a 3-inch pipe that 
enters the kettle just above the steam pipes. On inside of kettle 
this pipe is about 6 feet long and at the lower end is provided 
with two elbows which form a hinge, so that the pipe may be 
swung over and gradually lowered to a point just above the nigre. 
When soap is all out this pipe is drawn back to a vertical posi¬ 
tion by means of the chain attached to its top, and the mouth of 
pipe is closed with a cap attached to a 34 inch iron rod, with a 
“T” handle, that reaches to the top of the kettle. 

“Running across top of the kettle is a shaft, for which 1^ 
inch extra strong pipe will answer, and mounted thereon is a reel 
or paddle wheel as shown in Fig. 16, page 104. . 

“The arms or spokes of this reel are made of yi x 1*4 inch 
iron and are 16 inches long from center of shaft to end of the 
arms; the blades, four in number, are }£ x 4 x 24 inches, and we 
find this size reel amply sufficient to hold down the soap. In our 
factory these reels are driven by a small special engine, which 
also drives the fans for keeping the air in motion in the Boiling 
Room; they require little power, and the work performed by them 
as compared to the work of a paddle or shovel in the hands of a 
man, is like the work of a steamboat wheel and that of a boat 


Arrangement for 
preventing boil¬ 
ing over. 


104 


The Soap Factory. 


oar. This apparatus has been in use in some factories of our 
country for many years. 

“To prevent the soap from cooling* too rapidly around the 
sides of the kettle, this is jacketed from the bottom to the floor 
above, with 2-inch wooden staves, and to prevent the heat and 



Fisr- 10. 


steam of the kettle from filling the Boiling* Room to the discomfort 

of those employed therein, the kettle is encased from its top to 
the floor next above. On this floor the rosin is broken up and 
through a chute is conducted into the kettle. By this arrange¬ 
ment two men can easily do the work of four that have to shovel 
the rosin over the side of the kettle, and all rosin dust is kept 
out of the Boiling Room. From rosin floor to the roof and a few 
feet above, a suitable chute (ours are made of sheet iron and are 
5 feet in diameter) carries the steam out of doors. This chute is 
provided with a cut-off or damper to prevent the cold air in win¬ 
ter from descending into the kettle when not a-boiling. 

“The fats, lye, water or brine run into this kettle through 
a system of pipes under the control of the soap boiler or attend¬ 
ant, and the finished soap runs out through the 3-inch pipe men¬ 
tioned above. The time required for framing a 50,000 to 60,- 
000 lbs. patch is from three to four hours.” 

The next illustration (Fig. 17) is a sectional view of a ket¬ 
tle, arranged somewhat similarly, but having vertical walls, and 
the closed steam pipe arranged “criss-cross” instead of spirally. 
This pipe is less expensive and for not too large kettles just as 
effective as a spiral coil; it covers the bottom of the kettle to 
within about a foot of the walls, the space left free being required 
for convenience in cleaning. For larger kettles this pipe has the 














The Soap Factory. 


105 


disadvantage that the hottest steam is all on one side of the ket¬ 
tle, and the boiling thereby apt to be uneven. The open steam 
coil has a diameter about # that of the bottom of the kettle; its 
perforations are similar as already described, their total area not 
to exceed the capacity of the pipe. The valves for opening and 



Fig. 17. 


turning off the steam in the pipes are placed (in both kettles 
shown) near the bottom of the kettles, so that on turning off the 
open steam the condensing steam in the pipe will not, by creat¬ 
ing a partial vacuum, cause the soap to be forced up into the pipe 


























































106 


The Soap Factory. 


and choke it on cooling". In other factories, again, the steam 
pipes enter the kettles from above, passing - over at the rim and 
running to the bottom of the kettle along the inside wall; thus 
the pipe does not need to perforate the kettle wall, but in this 
case the valves cannot be so conveniently placed as just described. 
Both, the open and the closed pipe are 1 to \% inch for a kettle 
of 60—80,000 lbs. capacity. The soap outlet pipe has already 
been described, and is shown in the last illustration as entering 
the kettle at a point above the “nigre” or dark soap. Its inlet 
is turned upward, which facilitates drawing off the soap from 
the nigre. Others prefer this opening turned downward, so that 
it can be used to draw the soap from an iron bucket sunk into the 
contents of the kettle, in such a manner that it may be conveni¬ 
ently employed to draw the last of the clean soap off from the 
“nigre” underneath, the soap being collected in the bucket and 
drawn off through the pipe. When not in use the inlet of the 
pipe is closed, as described before; a strainer may also be pro¬ 
vided on the inlet, to prevent sticks or dirt from entering which 
might become lodged in the elbow joint of the pipe. In the case 
of boiled-down soap such as “German Motted,” which is very 
thick and not only difficult and slow to pump, but also liable to 
become frothy through pumping, some factories use a separate 
5 or 6 inch valve in the side of the kettle, connected with a pipe 
in such a manner that a large funnel can be inserted through 
which the last soap can be dipped out. The crutcher is then 
most conveniently placed near the bottom of. the kettle. Instead 



of the single valve shown on the outlet at the bottom of the 
kettle, two valves may be placed to advantage, one below the 
other as shown in the illustration above. 





The Soap Factory. 


107 


This arrangement not only provides against accident in 
case the single valve fails to close for any reason, but, by con¬ 
necting a steam pipe between the two valves, any soap that 
may clog the lye outlet may be blown back; the kettle may even 
be temporarily heated by this steam connection, in case the 
open steam coil should have become clogged up by chilled soap. 



lig. 11). 

Fig. 19 represents a similar kettle as made by the Hersey 
Mfg. Co., of sheet steel and heavy angle iron around the top to 
make it rigid; the cast iron supporting pieces can be attached at 
any point ordered. 

Some years ago a steam coil was adopted in many factories ^^eau/cons 
which, instead of over the bottom, was placed close to the walls 















108 


The Soap Factory. 


Mechanical 



1 ig. ‘20. 

A convenient and effect : ve combination of the several coils 
mentioned is illustrated by Figure 21, page 109, Farrell & Rempe 
Co., of Chicago, manufacture these coils. 

Thirty years ago mechanical stirrers were frequently used 


of the kettle, running spirally along their inner surface for two 
or three feet in height. This form of coil was, however, soon 
abandoned again in most factories, as the low coil near the bot¬ 
tom has the advantage of being mostly immersed in lye and thus 
keeping the soap from sticking to it; the high coil did not have 
this advantage, and, furthermore, the hot steam entering on the 
top cools off so much before reaching the bottom of the kettle, that 
in large kettles sometimes only the upper part of the contents, 
and that near the walls of the kettle, could be made to boil. The 
latter difficulty, however, could be at least partly avoided by 
running the steam pipe down almost to the bottom and then coil¬ 
ing it upward. In order to secure an even boiling throughout 
the kettle, the best plan is undoubtedly to have the closed coil 
placed flat over the bottom of the kettle, running it in the centre 
first—so that the hottest steam is in the middle—and then coil¬ 
ing it around to gradually approach the walls of the kettle, as 
shown in the next engraving. 


rers. 













The Soap Factory. 


109 


to help stir the contents of the kettles. They have since been 
discontinued in nearly all cases, but at times they are quite con¬ 
venient to have, and may yet come into use again for the smaller 
kettles more than they are at present. 

In regard to the use of steam, it may also be mentioned that Open vs. closed 
while both open and closed steam are found desirable by the great steam ' 
majority of manufacturers, there are those who advocate the use 



Fig. 21. 


of open steam only, arguing that the closed steam pipe is a relic 
of the days when impure caustic made the use of weak lyes neces¬ 
sary, in consequence of which the excess of water present makes 
the further addition of water from the open steam undesirable, 
that now the use of purer caustic permitting the use of strong 
lye, there is no need for closed coils. There are also those who 
even believe that closed steam is all-sufficient, but these are mat¬ 
ters which will probably never be settled to the satisfaction of 
all. One thing to guard against is too great number of holes in 
the open steam pipe, as this leads to insufficient boiling on one 
side of the kettle, and in several cases an uneven product of soap 
in consequence, the feed pipe being unable to supply steam to all 
the perforation. The steam is used at a pressure of 3 to 4 at- PresMlveolsteam 
mospheres (one atmosphere = 15 lb?.) Super-heated steam, as 
sometimes recommended, is hardly used. If much water is to be 


















110 


The Soap Factory. 


Jacketed kettles. 


* 


•y* 


evaporated from a soap, a pressure of 5 atmospheres is quite suf¬ 
ficient. 

The steam, which has spent most of its heat while passing 
through the closed coil, is condensed into hot water on issuing 
from the coil, and can be used to advantage for various purposes, 
as for dissolving caustic, thus utilizing the heat it contains and 
also taking advantage of the purity of the distilled water. 

It still remains to mention the jacketed kettles, with double 
walls at the lower part, between which steam circulates. This 
arrangement is not adapted for large kettles, nor indeed very 
practical in any ordinary case where a soap is to be boiled, as the 
dirt accumulating on the bottom prevents the heat from being 
properly effective. When used, the bottom should not be rounded 
too much, but be flat and the jacket should not extend too far 
up, as otherwise the soap might boil in the upper part of the ket¬ 
tle only, and not at the bottom. If the fats are previously well 
clarified, for making fine toilet soaps, these kettles have the 
advantage that they can be cleaned more thoroughly, and that 
there are no steam pipes at the bottom between which undissolved 



Fig. 22. 


salt or strong lye might remain in spite of all boiling; in this 































































The Soap Factory. 


Ill 


case also there is no danger of wasting heat by accumulated dirt 
at the bottom. 

Dopp's Jacketed Toilet Soap Kettle: Within the C suspended 
above the kettle (see Fig. 22) there runs a conveyor-screw D 
resembling the screw in some crutcners described further on, 
which is very effective for mixing or “crutching” the contents 
of the kettle. The agitator is easily taken apart for cleaning 
purposes, by simply loosening a set-screw, and may be raised 
and lowered at will, as well as swung out of the way when not in 
use. 

For some purposes, notably in making half-boiled soaps, it 
is convenient to connect the steam pipe with a cold water pipe, 
in the manner shown in the accompanying drawing. This ar¬ 



rangement permits of rapidly reducing the temperature of the 
contents, if this should be necessary to prevent boiling over, or 
when the stock to be used is too hot. 

CONNECTIONS WITH KETTLES. 

In the matter of facilities for charging and emptying the 
kettles, regard must of course be had to the peculiarities of the 
factory and the soap to be made. A soap pump being a practi¬ 
cally indispensable machine around the factory, it is a good plan 
to connect the same with all the soap and lye outlet pipes, and 
to run the discharge pipes of the pump to all the other kettles 
tanks used in connection with them. In this manner all 
possible contingencies for the disposal of the contents of the 
kettles are provided for. In making these connections it is well, 
however, to bear in mind the possibility of small leaks in one of 









112 


The Soap Factory. 


V laci 
pum p 


the lye valves, which might cause lye to find its way into the soap 
being pumped and render it surprisingly “strong.” The pipes 
leading to the pump ought to have a valve near the tank, and 
one near the pump. So that no stock lye, soap, &c., can run 
into the pipe when pumping from other tanks. 

THE SOAP PUMP. 

Among the various pumps that have been constructed for 
the purposes of the soap factory, such as pumping grease to the 
kettles, pumping the soap to the crutcher, bringing lye to the 
kettles, &c. The Heksey pump (Fig. 24, 25, 26, 27,) the Taber 
pump (Fig. 28,) and the Johnson Rotary Pump, have come into 
wide use. 



Fig. 24. 


The Hersey pump is set up in any convenient position, not 
more than ten feet above the bottom of the kettles, but preferab¬ 
ly below the kettle, so that the soap flows into the pump by its 
own weight instead of requiring the pump to draw it upward. 
It is connected with the kettles, etc., as already described; and 
its discharge side should be connected with a steam pipe for oc¬ 
casional blowing back and cleaning. (A water pipe may be con¬ 
venient in connection with some pumps also, for the purpose of 
priming the pump in case it refuses to work, as may occur when 
the body to be pumped is so warm as to give off vapor which des¬ 
troys the vacuum). Valves are placed in the connecting pipes 
























































The Soap Factory. 


113 


so that the pump can draw from and discharge into any of the 
kettles and tanks without disturbing the others. The special 
feature of this pump is that it conveys not only soap, but also 
hot as well as cold oils, lye of every description, and water. 
With a speed of 120 revolutions per minute, the three sizes have 
a capacity 3,000, 6,000 and 10,000 gallons per hour, respectively. 
The blade B swings on a pivot, and the cone-shaped piece D, by 
its contact with the cover, maintains a division between the two 
sides, so that in sweeping around the blade B, running in the 



Fig. ‘25. 


direction of the arrow, draws the soap in at A and discharges it 
at C, emptying the pump twice in each revolution. 

The opening marked A in the sectionial view is the suction 
when the pump is run in the direction of the arrow; on reversing 
the machine the same opening becomes the discharge, and the 
opposite opening will then be the suction. The outlets are 2 to 
3 inches in diameter, according to size of pump, and correspond 
to the size of the discharge pipes of the kettles as generally used. 

In connection with the pump should be a belt-shifter so ar¬ 
ranged that it can be operated by means of a rope from any floor 
of the factory. 

Fig. 27 shows above pump combined with engine. The 
latter is provided with a pulley from which any other piece of 
machinery can be driven. 

Working on a different principle, but also very effective are 
the Taber soap pump shown in Fig. 28; the Johnson Rotary 
Pump, Fig. 29, 30, 31; and that made by Brown & Patterson, 
Fig. 32. For soap factories these pumps are made of iron, but 
steel or bronze pumps for special purposes are made by the same 
firms. 

In the foregoing pages has been described the machinery 















114 


The Soap Factory 











































The Soap Factory. 


115 


required for converting- fat and alkalies into soap; but there 
still remains to be considered a number of machines and appli- 



Fig. 27. 

ances necessary to form the bulk soap contained in the kettle 
into a merchantable bar or cake. Prominent among these are 
































116 


The Soap Factory. 


Cleaning the 
Crutcher. 


Crntcbingair into 
•soap. 


THE CRUTCHER AND THE REMELTER. 

The name “crutcher” is derived from the old fashioned 
crutch-like stirrer which was in use before machinery took its 
place, and as the old hand crutch was—and to some extent still 
is—employed for several uses, so the machines now serve a variety 
of purposes; all these uses, however, are based on its action as 
a mixer or as agitator. 

In size these machines correspond with the capacity of the 
“frames” to be described later, which ordinarily hold about 
1,200 lbs. 

A few minutes agitation in the crutcher suffices to thorough¬ 
ly mix a batch of soap with the ingredients added, and the con¬ 
tents are then emptied into the “frame,” for which purpose the 
crutcher is so placed that the soap can run directly into the 
frames placed underneath. 

Immediately after emptying, these machines may be cleaned 
by running through them boiling hot water, or filling them with 
water and bringing it to a boil by an open steam pipe, or by 
letting open steam through the covered apparatus; but if the 
soap is allowed to get cold in them, the cleaning operation is 
more difficult and tedious. 

It should be noticed that some styles of crutchers are made 
either with or without a steam jacket. While it is not generally 
required for simply mixing soap with the filling, the steam jacket 
is often a desirable feature, as when the machine is to be used 
as a remelter for scrap soap; or when the soap has cooled off too 
far before crutching; or for making soap by the cold or half- 
boiled process. 

In the following are described the principal styles of crutch¬ 
ers as well as remelters in use. As some of these machines serve 
for both purposes, they cannot well be considered separately. The 
machines described are all admirably adapted for their purpose, 
and are preferred according to individual requirements or per¬ 
sonal preference. In a general way it may be said that some 
crutchers have a stronger tendency than others to crutch air into 
the soap, and this may often lead to decide a choice between the 
different styles. Air crutched into soap brightens its color, but 
at the same time makes it more dull and opaque. 

Doll’s Crutcher is one of the simplest forms of this ma¬ 
chine. It consists of a simple tank, having a soap outlet at the 
bottom. Within it is placed a cylinder, open on top and bottom, 


The Soap Factory. 


117 


resting - on leg’s. In this cylinder runs a screw, as shown in sev¬ 
eral illustrations hereafter, which catches the soap at the bottom 
of the apparatus and carries it to the top of the inner cylinder, 
o^er whose rim it falls back into the space between the inner 
and outer cylinders, to find its way gradually to the bottom 



Fig. 33. 


ag-ain. This mixer is designed especially for mixing the soap, 
while still warm and soft, with “filling,” such as sal soda, 
silicate, etc. 

A modification of the apparatus is shown above, the object 
of which is not only to mix the soap and filling, but also to re¬ 
melt the scraps and cuttings of soap on hand, that require work¬ 
ing over to be salable; or to manufacture soap by the cold pro¬ 
cess and remelted toilet soaps. In this apparatus the inner cy¬ 
linder ( A ) is jacketed, and the legs (2?) supporting it are made 
of gas pipe, through which steam may be admitted to the jacket. 
Open steam may also be turned directly into the soap by means 
of a single perforated coil near the bottom of the mixer. As the 
scraps of soap are carried upward by the screw they are thus 
heated by the open and closed steam until they become soft 
enough to be forced through the sieve placed above the cylinder. 



























































































































118 


The Soap Factory. 


The sieve consists of two halves which are held in position by 
the arms E , and is readily removable. 

The driving- parts of the machine are so arrang-ed that they 
can be quickly reversed, to facilitate emptying- the crutcher. 

This machine, plain or with remelting- apparatus attached, 



Fig. 34. 


is also made (single or double) connected on one frame with a 
steam engine, as shown on illustration herewith. 

Atkiss’ Mixer. The principle of mixing- soap by this ma¬ 
chine is evident by a glance at the illustration. The wing-s on 
the central shaft, as shown, have a slanting- position, and in ad¬ 
dition are raised and lowered as indicated by the dotted lines. 
(Fig-. 35.) 

Strunz’ Crutcher. The interior view of this machine also 
explains itself. Soap is run in until the wing-s are one or two 
inches more than completely covered and the crutcher is set in 
motion in the direction required to work the soap toward the 
outlet, the central shaft making- 45 to 50 revolutions per minute. 
While emptying- the contents into the frame, the paddles should 
not be running-, unless the soap runs out very slowly. 

This style of crutcher is also made with a steam jacket, as 















The Soap Factory. 



Fig. 36.—Outside View of Machine. 


119 















































































































































































































































































































































































120 


The Soap Factory 



shown in the next illustration. The direction of the steam or 
water, as the case may be, as it circulates through the machine, 



Fif. 38.—Jacket View of Machine 











































































































































































The Soap Factory 


121 


is indicated by the arrows ; also the pipe through which they 
escape. The valve at the bottom is for the purpose of drawing* 
off the water left in the jacket at the end of the operation, which 
should never be overlooked, as its presence would cause a strain 
on admitting* steam, or in cold weather even freezing* and burst- 
ing* of the jacket. To clean the machine when necessary, a few 



pailfuls of salt water at 22° are added, and the machine set into 
motion for a few minutes. The escape steam pipe of the 
jacketed machine should be left free, that is to say, it should 
have no valve attached to it. 

Recently F. B. Strunz of Pittsburgh, Pa., has iitroduced an 







































































































































































































































































































































































































































































122 


The Soap Factory 


improved Strunz crutcher which cools and heats the contents 
quickly, as desired, and in which it is impossible for any of the 
paddles to become detached or break off. It works thoroughly 
and rapidly and allows no air to mix with the soap if the mach¬ 
ine is filled above the top of the paddles, the soap coming out 
particularly clear; when filled to within a few inches from the 
top of the paddles, the soap quickly becomes aerated up to the 
point of floating. Highly filled soaps and mineral scouring soap 
even can thus be made light enough to float. 

Houchin & Huber’s Crutcher. This machine consists of 
an outer shell made of two shells of boiler steel riveted together, 



Fig. 40. 











































































































































































































The Soap Factory. 


123 


so as to form a steam jacket, which extends over the whole bot¬ 
tom and up the whole side of the machine. An inner drum of 
like construction, except that it is open top and bottom, a con¬ 
veyor screw to carry contents up inner cylinder and over and a 
means for operating- same with overhead shaft and g-earing-, in 
tvym operated by an engine of modern construction. 

Owing- to the peculiar construction of the outer shell, the 
heating- capacity of the same is very large, much more so than 
any machine so far designed and being constructed like a boiler 
and thoroughly stay-bolted cannot burst under ordinary steam 
pressures. Being wrought steel and no thicker than required, 
can also be cooled much quicker in operation than where a large 
amount of cast iron need be cooled. 

The shell can never crack in cold weather, like cast iron and 
as a drip is provided in the exact center or lowest part of the 
bottom, will drain itself perfectly at any time. 

Dopp’s Crutcher and Remelter. This apparatus is made in 



FijLr. 41. 





























































































124 


The Soap Factory 


two styles, that is to say, it is arranged either with or without 
a steam engine of its own. While, therefore, in the latter case 
the machine is driven by a special shaft and belt, the one with 
an engine of its own not only works independently from all other 
machines in the factory, but can be used in addition to transmit 
power (while the crutcher is either running or standing still) to 



run the elevator, or the soap pump, or such other machinery as 
may be in the factory. 

This crutcher and remelter consists of a steam jacket and 
an inner shell, cast together in one piece, and having a large 
outlet in the center of the bottom for discharging the contents. 












































































































The Soap Factory. 


125 


In the center of the kettle is placed a steam heating - radiator 
formed by a system of vertical pipes arranged cylindrically, and 
with open spaces between them; steam passes through this radi¬ 
ator into the jacketed part of the kettle, but can be cut off so 
that only the inner cylinder has steam. A conveyor screw is 
placed in the center of this radiator for mixing the soap. 

When the machine is to be used for remelting, it is filled 
with soap scraps, covered up, and the steam at a pressure of 
about 20 lbs. is turned on; too high pressure may scorch the 
soap. As soon as a portion of the soap is melted the screw is 
set in motion. Open steam may also be turned into the soap to 
moisten it, if necessary. The motion of the screw lifts the soap 
and throws it over the the top of the radiator and partly forces 
it through the open spaces between the pipes. The pieces that 
are too large to pass in this manner are carried up and wedged 
in between the open ports, formed by the upper ends of the 
steam pipes. By the motion of the screw the pieces are sheared 
off and thus completely cut up. 

When required for cooling, cold water may be passed, in¬ 
stead of steam, into the jacket and the radiator. The screw 
may be run forward or backward, the change being effected by 
simply shifting the gearing. If it is found that the soap has a 
tendency to become spongy while lying in the hot jacket, steam 
to the latter must be shut off. 

The engine connected with the crutcher, as shown in Fig. 
42, is one of eight horse-power, and is, therefore, sufficient not 
only to drive the machine, but run an elevator, and pump soap 
at the same time, (or do the latter work alone while the crutcher 
is not in motion). It dispenses with all shafting, pulleys and 
belting for crutching, and may consequently be set up in any 
place desired. All that is necessary is to connect the machine 
to a boiler having 40 lbs. or more of steam. 

It is an extremely convenient apparatus, not only for remelt¬ 
ing, but also for mixing and for making soaps by the cold 
process. 

Whitaker’s Remelter. This is a machine specially design¬ 
ed for the remelting of soap, whether for working up scraps or 
for making remelted toilet soaps. It consists of the wrought 
iron cylinder A into which is set the continuous steam pipe B 
connecting with the horizontal pipe b. These pipes rest on a 
wire netting through which the melted soap may drain off. F 


126 


The Soap Factory. 


is a perforated pipe for admitting- steam into the soap throug-h 
the valve /. The condensed steam is drawn off by pipe/. 



When the apparatus is filled with soap it is covered, and 
open steam turned on. When the scraps begin to melt, the open 
steam is shut off, the condensed steam drained off, and closed 
steam turned on. The melted soap is drawn into the frames as 
it melts and occasionally crutched through; or the soap is run 
from the remelter into the crutcher and there worked through 
before framing. 

The time required for the operation depends on the dryness 
Accelerating the ^ scra p S f or the more water the soap contains the more 

melting. ... r 

quickly will it melt. Ten to twenty frames of soap scrap can be 
remelted in a day by this machine, when used as described. In 
large factories where there is considerable work for the remelter, 
it is a good plan to provide it with a high “curb” into which the 
scraps are thrown as fast as they come from the cutting ma¬ 
chinery. The pressure of the great amount of scraps above 
serves to press the remelted soap out quickly, thereb}Mncreasing 
. the capacity of the remelter considerably and improving the pro- 























































































































































































The Soap Factory. 


127 


duct. At the same time the curb, if properly arranged, will pre¬ 
vent the rapid drying of the scrap, which circumstance also in¬ 
creases the capacity for remelting. Lastly, the curb may pass 
through several stories, with doors through which the scraps 
may be thrown into the remelter, whereby work in handling 
them is saved. 


THE SAL SODA TANK. 

As “sal soda” filling is now very generally made from soda 
ash, it is well to remember that soda ash is more soluble in 
water at 100 u than it is in boiling water; it is therefore sufficient 
to have the water at 80° when the soda ash is put in. To facili¬ 
tate solution by means of agitation, if there is an air pump in 
the factory, the sal soda tank ma} r be connected with it. The 
process of dissolving raises the temperature of the water consid¬ 
erably, but by making the solution in the manner here indicated 
it will have the right temperature for use as soon as it is strong 
enough and has settled out the impurities. To prevent boiling 
over when made in the ordinary way, the tank should not be high 
and narrow but rather low and wide. The steam (or air) pipe 
somewhat resembles the open steam pipe as described in connec¬ 
tion with the soap kettle, and should have the perforations at 
the sides of the pipe (instead of on top) so as to keep the soda 
ash from settling down to the bottom of the tank as it would if 
the holes faced upward. In this case also, the capacity of the 
perforations should not exceed that of the pipe itself, in order 
that an even pressure may be forced through each hole, and the 
solution should also be drawn off two to four inches above the 
bottom so as to keep the sediment out. The valve should be a 
double-gated one, as it sometimes happens in winter that the sal 
soda crystallizes in the pipes and it may become necessary to 
heat it or drive a rod through the pipe; another way of obviating 
this difficulty is to use a double-jointed draw-off pipe in the tank 
like that used in the soap kettle. 


SOAP FRAiTES. 


When the soap is finished in the kettle, and has received the 
required additions in the crutcher, it is run into the soap “frames” 
for cooling and hardening. These frames are made either of 
wood or of iron, the latter being the kind most generally used in 


Wood and 
frames. 


Iron 


128 


The Soap Factory. 


this country. Wooden frames, which are considerably lighter 
and therefore easier to handle, naturally retard the cooling of 
the soap, and are therefore mostly used for special kinds of soap 
which require slow cooling. The iron frame, as generally used 
for common laundry soap, is in most cases of a size holding about 
1,200 lbs. 

Whitaker’s Patent Soap Frame has a wooden bottom 
mounted upon truck wheels for moving it about the factory, 
and two sides of sheet iron, flanged at their upper edges, and 
strengthened by ribs of corrugated sheet iron running in the 
direction of their length on the outer surface; this device pre¬ 
vents the sides from twisting or bending, so that the soap will 



Fig. U. 

set in the exact rectangular shape, on cooling. 


The sides are 
















The Soap Factory. 


129 


connected by ends of two inch plank and secured by clamps, 
allowing-of mounting- and dismounting- the frame almost instantly. 
In such iron frames ordinary soap cools sufficiently to strip in 
from 24 to 48 hours, according- to the weather and temperature 
of framing-. The averag-e size of this frame weig-hs about 370 
lbs. The frames are made to order, in every size and shape 
desired. 

When so ordered these frames are made water-tight with 
rubber packing, for special use. 

Dopp’s Soap Frame. The illustration of this frame explains 
itself. 

HoucHin & Huber’s Soap Frame. (Fig. 45.) This frame 
has quick acting adjustable end clamps. These clamps may be 
taken up in an instant, without a wrench or tool of any kind. 



Fig 1 . 45. 


So if an end does not clamp tightly, a single turn of this device 
will generally suffice to make a tight frame. A patent nas been 
applied for. 













































































































































































































































































































































































































































































































































































































































































































130 


The Soap Factory. 


Home-made Frames: A cheap, convenient, and easily 
handled, as well as quickly cooling-frame may be made according 
to the following- description, given by a writer in the American 
Soap Journal. The sizes mentioned are for a frame holding- 
1,200 lbs. of soap. 



Fisjr. 40. 



Fig. 47. 


Fig-. 46 shows the frame ready for use, but empt}-, the sides 
being: of steel of No. 12 thickness and the ends of wood. The 

o 

sides have lj4 inch angde irons, running- lengthwise, three in 
number, to strengthen them, and also at each end perpendicularly 
a tapering angle on which clamps work, to bring the sides up 































































































































































































































































































































































































































































The Soap Factory 


131 


rigidly when the clamps are driven down upon the tapering angle 
irons, which near the bottom assumes its full size of 1J4 inches 
in width. On one end of the frame is partly shown a com¬ 
bined wood and iron clamp, one of a pair used only when running 
the frame away from the crutcher, on and off elevators, and over 
rough floors while the soap in the frame is still hot. 




Fig. 49. 



Fig. 50. 


In this cut is seen one of the center wheels, 9 inches in diam¬ 
eter, on which the frame principally rests; at each end, not dis¬ 
tinctly shown in the cut, is a pair of inch wheels, hung to¬ 
gether on a swivel, in the form of a castor, which failing to more 
than barely touch the floor lightly, if at all, enables the frame 
to be easily and quickly revolved on its axle. The end pieces are 
simply wooden planks, say inch thick with one inch battens 
as shown. For convenience in every way a frame of the capacity 




































































































































































132 


The Soap Factory. 


stated may be made, inside measures, say 54 inches in length, 40 
inches in depth, and 14% inches in width, and in making out 
specifications for the iron work allowance, of course, must be 
made in addition to these figures for the thickness of wooden- 
ends, say 5 inches, and for a false bottom of say one inch. One 
inch axels of steel should be used for the wheels. 

Fig. 47 shows the steel side, removed from the frame. This 
should be made straight and flat. 

Fig. 48 shows the frame bottom, top view, which needs no 
further explanation, as the cut speaks for itself. 

Fig. 49 shows the reverse of the same. The bottom may 
be made of 2 inch plank, 5 feet 3 inches long, 20 inches wide, 
with say four battens on under side, 2x4 inches, and with 
wheels placed as shown. 

Fig. 48 shows cleats 2% inches in width and a false bottom 
54 x 14% inches, and one inch thick, placed relatively with 
spaces for receiving and retaining in position the sides and ends. 

Fig. 50 shows the steel clamps, one somewhat shorter than 
the other, at each end of the frame, 2 x % inch, curved at ends 
to fit upon the tapering angle iron on frame sides to hold the 
whole rigidly in position. It also shows the wood and iron clamp 
for temporary use, as before referred to. The iron castors can 
be obtained through any large hardware house. The iron 
center wheels should be made light, but strong, say of two inch 
face. 

. Constructed of steel not unnecessarily thick, these frames are 
readily taken apart and set up again by even two boys, and when 
filled with soap they can be easily moved about on a smooth floor, 
and can be turned completely around within the space of their 
own length by one boy alone. When set up, the clamps hold 
them together very rigidly, making a very strong frame. 


Track for the 
frames 


Extra bottoms 


In factories where many frames are used, it is convenient to 
have a track on which fit the wheels of the frame, so that the 
soap can be easily wheeled from one room into the other. In 
this case it may be best to have the wheels so placed on the bot¬ 
tom of the frame that the latter stands crosswise on the track. 
The size of a 1,000 lbs. frame being about 14 x 56 inches, (and 
about 40 inches high) much space on the track is saved by hav¬ 
ing the wheels placed in this manner. 

It is also found convenient to have one extra bottom for each 



The Soap Factory. 


133 


frame, for while one bottom is occupied by the block of soap 
after it has been “stripped,” the extra bottom, together with the 

sides and end pieces taken from the first bottom, can be used for 
the next framing. 

Where frames are used that have no wheels, they are placed 
below the crutcher on “run ways,,’ in such a manner that the 
frame stands high enough above the floor to readily permit of 
pushing a truck or ‘‘buggy” underneath them. This buggy is 
made of iron and so constructed that, on raising the handle, its 
frame work is raised sufficiently to lift the soap frame off the 
run ways. On wheeling the truck to another part of the factory 
and lowering the handle, the frame is also lowered and placed 
on similar run ways provided for the purpose near the cutting 
machinery. 



Fig. 51. 

Instead of the “run ways,” and the special truck described, 
another contrivance is used in some places which consists of a 
number of pieces of gas-pipe, through which rods are passed 
to serve as axels for the pipes which in turn are used as wheels. 
The axels are placed parallel to each other and their ends se¬ 
cured in a frame-work. The frame bottoms are slightly curved, 
so that this apparatus can be easily slipped under them. 

While the iron frames, as said before, are those generally 
used for most soaps, some manufacturers still prefer the wooden 
ones as, on account of their light weight, they are easy to handle; 
nor do they become rusty and stain the soap, but on the contrary 
become covered after a short use, on their inner surface, by a 
glossy enamel-like coating, and therefore strip easily. 

For quite small frames, such as are used to advantage for 
some cold-made soaps, a cast iron box is well adapted, which is 
cut in half through the sides and bottom. For setting it up, it 
is only necessary to place the two halves together and secure 
them by a clamp. 


Trucks. 


Wooden frames. 


Small cast iron 
frames. 





134 


The Soap Factory. 


THE SOAP SLABBER AND CUTTER. 

The block of soap left on the bottom of the frames after 
stripping* is cut into marketable sizes by means of wire. The 
manner in which this operation was first performed was by mark¬ 
ing the block where it was intended to be cut, and simply draw¬ 
ing a wire through it along these marks. In some factories this 
simple process is still employed, but for large factories a 



Fig. 52. 

machine, somewhat on the plan shown herewith, will be practically 
indispensable on account of the saving in time and labor eff¬ 
ected by it. The illustration (Fig. 52, made by the Hersey Mfg. 
Co., and known as the “Ralston Slabber”) shows how the wires 
cut the block into slabs in an exceedingly short time and with 
the greatest possible regularity. The slabber should have a size 
corresponding as closely as possible to that of the frames, so that 
the cutting wires are just long enough to cut the block of soap; 












































The Soap Factory. 


135 


too long- wires are apt to break, owing- to the greater tension 
required to keep them in a straight position. The machine is 
mounted on wheels, so that it may be readily moved from one 
frame of soap to another. For slabs of varying thickness it is 
most convenient to have extra “reeds” which can be readily 
changed. As these machines, to give the greatest satisfaction, 
should correspond in size to the frames, it is necessary to have 
regard in their construction to the following measures; inside 





•) 


length, width and depth of frames, diameter of frame wheels, 
length of axle, and of course thickness of slabs to be cut. 

Another slabber is shown in Fig. 53, and is made by Brown 
& Patterson. 

Another slabber is made by Houchin & Huber. See Fig. 54. 

Fig. 55 is a rough sketch of the principle on which a home¬ 
made slabber may be constructed. 

For cutting the slabs up into long bars and into cakes, 
machines of various construction are used, as may be best adapted 




































































































































136 


The Soap Factory 


to the requirements of the factor} 7 . The accompanying' Fig - . 
56 and 57 hardly require further description, the mechanical de¬ 
tails appearing - plainly; nor can we describe all the forms of this 
machine in use, since they are frequently made accordidg to 
order, to comply ^ith individual needs and preferences. 



Fig. 54. 


Fig. 58 shows a soap cutter made by the Hersey Mfg. Co., 
of Boston. This machine cuts the slabs first into long bars and 
then into cakes, and then delivers them upon the “spreading” 
arrangement. 

Parallell staves are generally provided (see illustration) for 
the bars of soap to slide on after being cut; this arrangement is 
called a “spreader,” as by drawing the staves endwise the bars 



























































































































The Soap Factory 


137 


are spread slightly apart, in order to facilitate drying- on the 
rack, by allowing- the air to circulate freely among- the bars. An 
attachment for stamping- the cakes (if they are not to be pressed) 
may also be applied to this machine. 



Fig-. 50. 


According- to the needs of the factory, this machine is fur¬ 
nished with either adjustable wire holders for cutting- different 
sizes of bars and cakes, or separate reeds for the different sizes 
are kept on hand. 

Fig*. 57 represents a set of iron cutting- frames, as made by 


















































































































































































































































































138 


The Soap Factory 























































































































The Soap Factory. 


139 


H. Wm. Dopp& Son, of Buffalo. These frames are made of cast 
iron, and the wires are fastened and spaced as desired by means 
of thumb-screws. The frames are fastened by bolts upon a wooden 
frame as shown, and wooden bed plates must be provided for 
on the latter, as shown in the small engraving 1 forming part of 
the same figure. 



Fig. 59. 


As will be seen, the preceding machinery is run by hand, 
but there have also been made a few machines after a special 
pattern shown herewith, operated by steam power. (See 
Fig-. 59.) 

This machine slabs, cuts, racks, and spreads an enormous 
amount of soap per day. 

Another slabber and caking machine has recently been de¬ 
vised by Christopher Lipps of Baltimore, and still another set by 
Curtis Davis & Co. of Cambridgeport, but we have not room to 
illustrate them all. 

The wire used in these cutting machines is what is known 

































































































































































































































































140 


The Soap Factory. 


Planing thecalces 


Knives for cutting 
in place of wire. 


as “piano-wire,” which combines the greatest strength with 
durability, and is best adapted for the purpose because the thin¬ 
ner the wire the smoother will be the cut. 

For cutting - cakes from single bars the machine shown in 
Fig. 60 is a convenient arrangement. 

***** 

In the case of toilet soap, before pressing the cakes, (if they 
are to have a smooth surface) the bars after cutting and slightly 
drying are sometimes planed by drawing them over a machine 
arranged like an ordinary carpenter’s plane turned upside down, 



Fi£. 60 . 


which takes off a thin shaving and leaves the surface of the bar 
very smooth, giving the cake after pressing an improved appear¬ 
ance and decreasing its tendency of sticking to the dyes in 
pressing. 

Instead of wire for cutting the slabs into bars, steel knives 
or springs placed similarly in the cutting machines having been 
recommended. It is difficult to keep them from bending under 
the strain of cutting, and they are not widely used; but those who 
have tried them claim that they make a smoother cut than does 
wire. 

The thinner the cutting wire, the smoother will it leave the 
surface of the soap. 











The Soap Factory. 


141 


DRYING APPARATUS. 

After being- cut into bars the soap requires to be dried some¬ 
what in order to be in a marketable condition and ready to be 
pressed. This drying process is in many factories still carried Natural drying, 
out by simply placing- the bars on racks and leaving- them there 
exposed to the atmosphere until in the proper condition. This, of 
course, is an unsatisfactory method, as the changes of the weather 
render it very uncertain and tedious, besides being- slow at best 
and requiring considerable room. A somewhat improved result 
is secured from drying rooms in which steam coils are placed to . 

raise the temperature; here also, however, the air in the room 
becomes laden with moisture, and unless removed promptly, the 
drying- still proceeds in an unsatisfactory manner. The best 
results are derived, undoubtedly, by combined heating and ven¬ 
tilation. Currents of dry, warm air, directly acting- on the soap, 
hasten the process and dry the soap in a most satisfactory way, 
causing- the formation of a firm, glossy skin over the surface 
which greatly aids in pressing- the cakes and enhances their fine 
appearance. For this purpose a “blower” or “pressure fan” is 
placed before a steam coil (which may be heated with exhaust 
steam of the engine) and connected air tight with a casing sur¬ 
rounding- the coil. On admitting- air into the inlet of the fan it 
is forced throug-h the bends of the coil and its temperature there¬ 
by raised. As is well known hot air can absorb more moisture 
than cold air, and therefore whatever the weather may be, the 
soap is sure to be dried by directing the warm current upon the 
racks. From 6 to 12 hours' drying is ordinarily sufficient to put 
the soap in condition for pressing, whereas in the old way the 
time required is very indefinite. 

A convenient method of connecting the operations of ventil¬ 
ation and heating, for drying soap, is shown in the accompanying 
drawing. The latter represents a coil of 1 inch steam pipe (not 
shown) in a casing of sheet steel to which is attached a disk fan. 

The temperature of the air forced through the casing can be reg¬ 
ulated, and is generally kept at about 100° F. for soap. The 
soap in the drying room into which the hot air is forced may be 
placed on drying racks or on cars which may be gradually moved 
forward to the hottest part of the room as the drying proceeds. 

(See Fig. 61.) 

A similar apparatus, made by the Buffalo (N. Y.) Forge Co., 
is illustrated in Fig. 62, and requires no further explanation. 


142 


The Soap Factory. 




Inlet 


It is suggested that iti warm weather the coils of pipe may 
be filled with brine, which has the effect of condensing the moist- 


Fig. 61. 

ure in the air, thereby rendering its drying capacity, in passing 
over the soap greater. When the air is naturally in good con- 


Fig. <>*2. 

dition for drying, the coil may also be left out of use altogether, 
the fan only being used for ventilating the drying room. 

THE PRESS. 

For forming the bars of soap into cakes, presses of great 
variety have been constructed, ranging from the small hand- 
press which stamps a few hundred cakes per hour, to steam 
presses having a capacity of several thousand cakes in the same 
time. 

The machines used in most cases are operated by foot power, 

































































































































































































The Soap Factory 


143 


the steam presses being- mostly reserved for the larger factories 
which turn out large quantities of a few special brands of soap. 





















































































































































































































































































































































































































The Soap Factory 


145 



















































































































































































146 


The Soap Factory 


Hand-presses are used but little in this country, where labor is 
generally too expensive for their slow work. 

In selecting a press, regard is had not only to the require¬ 
ments of the factory as to capacity, but also to the special kind of 
soap for which it is to be used, for while most kinds are best pressed 
by a machine giving a sudden blow, others, it is claimed, form 



Fig. 69.—Horsey Mfg. Co.’s Steam Press, 
a better cake when compressed by a more continuous pressure, 
such as is given by the downward turn of a screw. If, as is gen¬ 
erally the case, the press is to be used for various sizes of bars, 

















































































































































































































































































































H. Win. Dopp & Son’s Steam Press. 


& 



T! 

cri’ 

Iv 

0 


148 




The Soap Factory. 


















































The Soap Factory. 


149 


the ready adjustment for different dies, and also for the force of 
the blow is to be considered. Ease of working, noiselessness, 
and stability are essential features, and it is also absolutely 
necessary that the guide for the dies be perfect, to insure the 
latter against undue wear. Lastly the arrangement for lifting 
the cake from the lower die must be so as to insure against 
defacing the impression by forcibly ejecting the cake against the 
top die. 

Herewith are illustrated a number of different soap presses, 
for foot and for steam power; it would lead too far to go into 
detailed descriptions of the same and their respective claims for 
superiority; we therefore contend ourselves with their illustration. 

Fig. 70, on page 147, represents a press which requires a few 
words of explanation. In this press the soap is handled auto¬ 
matically, that is, it is fed into the press and delivered there¬ 
from by belts, dispensing with the labor of putting the soap into 
the press a cake at a time by hand. The cakes from the cutting 
machine, after having been suitably dried on the racks, are placed 
on the upper belt shown in the cut and are delivered on to the 
lower belt after being pressed; from the lower belt the soap may 
pass to a table, or the belt may be continued in a horizontal di¬ 
rection, from which belt the soap is taken, or switched by foot 
to the wrapping table where it is wrapped and put in boxes 
immediately, the boys engaged in wrapping standing on either 
side of the belt and taking the soap as it comes along. 

The press is entirely automatic, feeding and delivering the 
soap by the mechanism perfectly, and it also thoroughly lubricates 
and cleans the dies between the pressing of each cake. It has a 
capacity of 360 boxes of soap of 100 cakes each per day of ten 
hours. The sdving of labor in the use of an automatic press will 
no doubt prove a very considerable item. The press is adapted to 
the pressing of all kinds and shapes of laundry soaps; the dies 
can be readily changed from one style or shape to another, and 
the pressure can be regulated at will. 

THE DIES. 

The dies in which the cake of soap is formed in the press 
require careful consideration, for on their construction depends, 
in a great measure, the appearance of the finished article, a mat¬ 
ter which has come to be of considerable consequence. 

We do not wish to say much about the material used in their 


150 


The Soap Factory. 




construction, as any manufacturer can buy good material. As 
long as a metal is used that will resist the corroding effect of the 
acids contained in soap, is tough and close-grained and the pro¬ 
per judgment and skill is exercised, a good die can be produced 
that will press any soap and in such a manner, as to produce a 
large-appearing bar with the least possible quantity of soap. 

Generally the entire set of dies is cast of the same material 
but sometimes there is substituted an iron box, lined with brass. 
This can be made a little cheaper, but when the die becomes 
worn there is no chance of refitting it, which easily can be done 
when the solid brass box is used. 

The design, lettering, ornaments, trade-marks etc., whether 



cut, raised or sunk on the die, should be made so, that it will 
readily shed the soap. At this point skill and experience on the 
part of the diemaker is required, as almost every grade of soap 
requires a different construction of the letter. 

A highly polished surface has no further advantage than to 
dazzle the eye and to conceal defects of the soap. An absolutely 
smooth surface, free from ridges, lumps and other irregularities 
should be looked for, as these will show the imperfections on the 
soap. Nickel and silver-plating has been resorted to to prevent 
corrosion, but when a good material is used and the dies are kept 


* 































































































































The Soap Factory. 


151 


clean, there is rarely any necessity for this additional expense. 

The dies may be divided into two principal classes, namely: 
Ordinary or box dies and pin or shoulder dies, of which illustra¬ 
tions are given herewith. 

The ordinary or box die, Fig. 74, consists of three parts, 
box, upper and lower dies. For laundry dies the box is gen¬ 
erally made four inches high and of sufficient thickness to 
prevent spreading. The upper die is about one and one-fourth 
inches thick and the lower die of such a height, that the upper 
die will not enter the box more than one-fourth of an inch. For 
toilet dies, the lower die is made from two and a half to three 
inches and the box of a corresponding height to accommodate the 
thickness of the soap. This die is suitable for all grades of soap. 




Fig. 75. 

A—Box. B—Upper Die. C—Lower Die. D—Shank. E—Fixed Panel. F—Changeable 

Panel. G—Flanges. 


Fig. 75, gives a sectional view of the ordinary or box die, 
































































































































































































152 


The Soap Factory. 


which we here illustrate for the purpose of g-eneral terms when 
ordering- either dies or panels, which will be found of mutual 
benefit for both the manufacturer of soap as well as the manu¬ 
facturer of dies, so as to avoid misunderstanding’s. 

The cut further illustrates the necessity of having- the inner 
sides of the box absolutely parallel. If, for instance, the inner 
sides were tapered and the die fitted so as to press a one-pound 
bar, the latter would fit the box snugdy. Should one desire to 
press a 12-oz. bar in the same die, it would be necessary to raise 
the lower die about one-fourth of an inch and there would be 
sufficient space to let the soap escape, thus forming a feather- 
edg-e. 

Though the illustration shows a fixed or solid panel in the 
upper die, laundry dies are now larg-ely made with loose or 
chang-eable pannels and thus an endless number of brands can be 
pressed in the same die. 



Fig. 715. 




































































































































































































































































































The Soap Factory. 


153 


This cut represents Christy’s Self Adjusting Dies which are 
similar in construction to the ordinary dies and are suitable for 
all grades of soap. They have in addition two steel guide-pins 
attached to the back of the upper die which enter into corres¬ 
ponding steel-lined holes in the box, thus accurately guiding 
the upper die to its place without the least danger of damaging 
the delicate edges. 



Hg. 7 7. 


Fig. 78, of another style die the box consists of two or more 
parts, grooved, tongued and securely bolted together, thus form¬ 
ing a box as strong as if cast in one piece. When the dies, after 
long use, become too loose, causing a feather-edge to appear, it 
is necessary only to separate the box, file off a trifle of the 
grooved surface and rejoin them and the die will be found in as 
perfect condition as when it was first received from the factory. 
This repair can be executed in the factory, can be performed by 
any employe and the die is always on hand when wanted and is 
easily kept in a perfect condition. 













































































































































































154 


The Soap Factory 



Fig. 78. 


This die can be made with or without the patent guide-pin 
attachment and is suitable for all grades of soap but especially 
for soaps of a gritty nature, for which it was originally intended. 
The pin or shoulder die of which we give illustrations of 





























































































































The Soap Factory 


155 


different makers, Fig-. 79, consists of two parts, upper and lower 



Fig. no. 



Fig. 81. 















































































































156 


The Soap Factory. 



dies. These dies are not practicable for the lower grades of soap 

and do not work well except in milled soap. 

The upper die has four lug's or shoulders, each supplied 
with a guide-pin, which enters into corresponding holes in simi¬ 
lar shoulders on the lower die, thus bringing the two halves 
together accurately. When pressing, these shoulders meet, pre¬ 
venting damage to the edges of the die proper. These dies are 
almost indestructible and have this additional advantage, that 
no matter how much soap is put into the die it will retain only 
the amount calculated upon, which in an expensive soap is quite 

an item. 


Fi£. 82. 

Christy’s Patent Combination Die, (Fig. 83), also made by 
several manufacturers, consists of three parts, box, upper and 
lower dies. The box receives the lower die, as in the ordinary 
























































































































































































The Soap Factory 


157 


or box die, but has in addition four lugs or shoulders, similar to 
those of the shoulder die, into which the guide-pins of the upper 
die enter, thus leading the latter into place. The upper die is 
similar to that of the shoulder die and if the lower die is fastened 
so that the top of same is flush with the top edge of the box, it 
will be a complete shoulder die. By a simple adjustment it will 
press a cake of any thickness as is done with the ordinary or 
patent dies and still has the advantage, that no matter how much 



Fig. 88. 


soap is put into the die, the intended amount only is retained, 
which, for the higher grades of soap, is worth considering. 
















































































































































































































































































































































































158 


The Soap Factory. 



Fig - . 85 represents an ordinary toilet set of dies showing- how 
interchangeable panels are set in dies. 

In this connection we illustrate herewith (Fig. 86) a very 
simple device for protecting- the workman ag-ainsta common form 
of accident while pressing- soap, in which operation a great many 
people have been more or less seriously injured. To prevent the 
workman from cutting off his fingers in the press, a block of 
wood is fastened to the right of the die box, conforming in size 
to that of the latter. Guides are provided in the form of two 





















The Soap Factory. 


159 



Fig. 85. 


strips, curved at the end to permit the bar of soap to enter read¬ 
ily. A bar is placed on the block and then pushed on the die 
box by another cake to be pressed next. When the first cake has 
been pressed the workmen can safely remove it while the top die 
is up; then the second bar is in turn moved forward by a third 
one being* placed on the block, and so on. After the workmen 
are once used to this arrang*ement there is no trouble whatever 
arising* from the use of this safeg-uard. 

An improvement in this direction has been suggested which 
consists in depressing* the wooden block about a quarter of an inch 
below the surface of the die box, and cutting* away the adjoining* 
























































































































160 


The Soap Factory 


side of the die box to the level of the block. In this case the 
cake of soap may be fed forcibly to the opposite side of the die 
box and held there momentarily by a light pressure on the extra 



cake; it will then fairly drop in on withdrawing the extra cake. 
Still greater safety is obtained by attaching to the face of the 
block an upright piece which will prevent the operator’s hand 
from passing over the die box when feeding the press. The work 



Fig-. 87. 

of the operator may be facilitated by having the block at least 
twice as long as the cake to be fed. This would enable him to 
place a cake upon the block with his right hand while the left 
hand is feeding the preceding cake in the manner described. 

The operation of pressing soap and the proper care oTthe 





































































































































































The Soap Factory. 


161 


dies will be described in a succeeding- chapter, but while on the 
subject of safety it should here be mentioned that in feeding- the 
ordinary press, without the safety devices described, the work¬ 
man should invariably handle the soap with the thumb and index 
finger of the hands, grasping- the bars midway between the upper 
and the lower surface. Nearly all accidents that occur are the 
result of handling- the soap by grasping- the bars with thethumb 
and middle finger, letting- the index fing-er project across the cake, 
and thus exposing- it to the dang-er of being- cut off. 

Fig. 88, shows an ordinary set of laundry dies with improved 
hand slide. These slides are made for feeding- with either rig-ht 



Fig. 88. 


or left hand. Some operators place a bar on the side and instead 
of following- it with a second bar, they push it into the die box, 
the bridg-e preventing- the fing-ers from being- crushed under the 
upper die, the top level of box being- hig-her than the surface of 
slide, it prevents the bar of soap from g-oing- over it, the bar 
being swiftly pushed, it is prevented from dropping into the box 
at an angle but will fall into proper place, flat on the top of 
lower die. 

































































































































































































































































































162 


The Soap Factory. 


HAND STAMPS. 

In place of pressing- the soap by means of press and dies, 
some soaps are merely stamped; this may be done on the cutting- 
table as stated already in the description of the soap cutter, or 
box metal or electrotype hand stamps may be used. These elect¬ 
rotypes should have clear, sharp letters and be heavily faced to 
withstand the wear. 



Fig. 80. 



Fig. 00. 


Fig. 01. 









































































































163 


The Soap Factory. 



Fig:. 92.—(See page 164.) 



Fig. 93.—(See page 164). 



















































































































































164 


The Soap Factory. 





JAM E S ATI<1 S S.MA 
2 TOMPKINS AYE 

BROOK.LYN.N.'r. 

^ PAT -applied 




vn I 


; lllialfflfl 
i i \i'a 


1 I |n 
iii i\i | 






THE SOAP CHIPPER. 

Instead of forming' the soap into stamped bars, it is often 
chipped up, especially for use in laundries, or when it is to be 
“milled.” Fig'. 92 and 93, show machines used for this pur¬ 
pose; the former is made by Brown & Patterson of Brooklyn, N. 
Y., and the latter by Rutschman Bros, of Philadelphia. 

The soap placed in the hopper is fed automatically to the 
knives. The latter are adjustable to cut different thicknesses. 
******* 

It only remains now to merely mention the simple tanks used 
for special purposes, as for bleaching - , for measuring' and storing - 
oils, for making- sal soda solutions, etc., and the ordinary machin- 


Fig. 94. 

ery used in all kinds of factories, as elevators, boiler, engine, 
shafting-, etc., and we may close this chapter, so far as a laundry 
and ordinary toilet soap factory is concerned. 





































































































The Soap Factory. 


165 


There are, however, the following- special machines still to 
be considered for factories making- “milled” toilet soaps. 

THE SOAP MILL* 

For making- the finest quality of toilet soap the process known 
as “milling-” is employed. The advantag-es of the same are 
obvious when it is considered that thereby perfume may be added 
to the soap when cold, that the soap is dried thoroug-hly before 
milling and therefore does not warp or shrink in the least, nor 
lose weig-ht, and that soap in general is improved by repeatedly 
working it over. 

The bars are chipped up, thoroughly dried and then fed into 
the mill where the soap is ground together with the perfume and 



Fig. 95. 


color desired. The mixture is passed several times through the 
machine until perfectly homogeneous. From the last roller the 
soap comes in a thin film that is cut automatically into narrow 
ribbons, which fall into a box placed under the machine. 



















































































































































166 


The Soap Factory 


The mills are made in various sizes and styles closely re¬ 
sembling* each other, so that the illustrations presented on pag*e 
164-165 will answer for all. Fig*. 94, represents a mill made by 
Brown & Patterson of Brooklyn, N. Y. Fig*. 95 is a mill made 



Fig. 90. 

by Rutschman Bros, of Philadelphia, Pa. Fig*. 96 is made by 
Houchin & Huber of Brooklyn, N. Y. 


THE PLODDER. 

This is a machine into which the soap is fed as it comes in 
ribbons from the mill, in order to form it, by an enormous pres¬ 
sure, into compact bars. Formerly machines were used which 
had to be refilled after compressing* a small quantity of soap with 
which they were charg*ed. At present, however, continuous 
plodders are in g*eneral use, from which the soap issues in one 






















































The Soap Factory 


167 



Fig. 98 
































































































168 


The Soap Factory 


continuous solid bar, so long- as more soap is fed into them. The 
soap, compressed by means of a screw which works the contents 
towards the outlet, issues from the nozzle seen at the left of the 
illustrations herewith, (Fig-. 97-98) and may at once be cut up 
into bars and pressed into cakes, without requiring- drying-. The 
opening- in the nozzle may be g-iven any desired shape by means 
of different dies, so as to approximate the shape of the cakes to 
be formed, and is kept warm by means of a g-as flame, so that the 
soap will come out smooth and gloss} 7 . 

These plodders are made with a jacket throug-h which cold 



Fig. \Hh 


water may be circulated to prevent the machine and the soap 
from becoming- hot throug-h continually working-the latter under 
so hig-h a pressure. It is found, however, that when heating 
actually does occur, the beet results are obtained b} T simply allow¬ 
ing the machine to rest until it cools off by itself. The bar of 
soap coming from the plodder is cut into short pieces, corres¬ 
ponding to the size of the cake, by means of the cutter illustrated 
on page 140. 

































































































The Soap Factory 


169 


Fig-. 98 represents the Atkiss plodder, made by Brown & 
Patterson of Brooklyn, N. Y. This machine, at each stroke, 
forces out a bar of soap from 3 to 5 feet in length. Its motion 
is continuous and the feed automatic. 

Fig - . 99 represents one of several styles of plodders made by 
Houchin & Huber of Brooklyn, N. Y. 

* ****** 

A new system of making- milled soap has been patented by 
a firm of soap manufacturersin Belgium, consisting of machinery 
in which by means of a system of hollow cylinders revolving at 
increasing rates of speed, and through which the air circulates, 



Fig. 100. 

hot soap directly from the kettle may be cooled down to the “sett¬ 
ing” temperature in a very few minutes; it is then carried on 
endless belts into a drying chamber into which hot air currents 
are introduced and from which it emerges sufficiently and evenly 
dried ready for the plodder. The perfume and color are added 
in a special mixing vessel just before the soap is brought upon 
the cooling cylinders. This system has not as yet been largely 












































































170 The Soap Factory. 

introduced into the United States, but is reported to give fair 
results, as it saves the time, k.bor and space now required for 
framing and cooling the soap in large blocks, only to heat it 
again for drying purposes after chipping it up. See illustration 
of this system opposite page 103. 

The smaller utensils, such as hand crutches, buckets, etc., 
have been so frequently described and are so fast disappearing 
in their use that a description is hardly necessary here. 

We represent herewith (Fig. 100) also one form of the many 
grinding mills used for making soap powder. This particular 
form, made by the Foos Mfg. Co., Springfield, Ohio, has been 
specially designed for this particular purpose. 

Finally, in addition to the pipes, valves, shafting, belting, 
&c., required in a factory of an} r kind, the soap factory requires 
such special apparatus for the economical use of steam in manu¬ 
facturing processes as reducing valves, steam separators, &c., 
one of which we illustrate herewith as representative of its kind 
i. e. the Eclipse Separator for live and exhaust steam, as devised 
by the John Davis Co. of Chicago. 















PART II. 




















































































































■ 















































































































CHAPTER VI. 


The Manufacture of Soaps. 


SELECTION OF MATERIALS AND ITETHODS. 

On commencing- the actual manufacture of a soap, a number 
of questions present themselves for the consideration of the man- 
facturer, which he must determine beforehand in order to obtain 
the desired results. Soaps for different purposes require different 
raw materials; the different treatment of the various materials 
requires different manufacturing- facilities. Ag-ainsoapsof certain 
characteristics are made by special selection of materials and 
methods, and according- to the equipment of a factory different 
means must be adopted at times for reaching the same or similar 
results. Closely interwoven with all these and other questions is 
always the matter of cost. 

We will here make a systematical survey of the preliminary 
questions to be answered. 

FOR WHAT USE IS THE SOAP INTENDED? 

This is undoubtedly the first question to be decided, as the 
adaptability of the soap to the purpose for which it is to be applied 
is important above all other considerations. It is obvious that a 
laundry soap must possess different qualities from a shaving soap, 
and that a tooth soap will not be popular if made on the lines 
which are applicable to a first-class scouring soap. 

Laundry Soap, as most popular in this country, is generally Stock for launch 
made of tallow and a moderate proportion of rosin. The tallow soa P s - 
may be partly or wholly substituted by grease, cotton seed oil or 
foots, palm oil, red oil, cocoanut oil, etc. The basis of this soap 
are the fats named, while rosin is used partly because it is cheaper 




174 


The Manufacture of Soaps. 


\ 


Effect of rosin. 


Hardening by sal 
soda. 


Unfilled laundry 
soap. 


Neutrality of toil- 
«t soap. 




than fats, and partly because on account of the easy solubility of 
rosined soaps they wash more rapidly than soaps made wholly of 
fat. The better grades of this kind of soap contain about 35 lbs. 
of rosin to hundred pounds of fat, too large amounts of rosin 
being* undesirable in a soap as making* it too soluble and sticky, 
and leaving* it with too little of the fat soap in which, after all, lies 
the principal value of a g*ood article, so far as washing* power is 
concerned. An addition of rosin just larg*e enough to effect its 
purpose is perfectly legitimate, and the evident preference of most 
consumers for such soaps refutes the argument sometimes made 
that rosin, even in small proportions, should be considered an 
adulteration. As by the addition of rosin the soap is softened 
somewhat, it is generally hardened by adding (in the crutcher) a 
strong solution of sal soda which, by crystallizing in the soap and 
by a peculiar effect on its structure renders it harder. In wash¬ 
ing this soda also aids in the cleansing effect of the soap, partly by 
promoting its solubility and partly by its own detergent properties. 
Some soaps are also made of fat and rosin, without filling; where 
their slightly slower work is not objected to, they may be consi¬ 
dered as ideal laundry soap(provided soft water is used with them), 
particularly in this country where the climate is such that a pure 
tallow soda soap would soon dry out to a point where it would 
become practically insoluble. Laundry soaps differ from toilet 
soaps in many particulars ; for instance, they are not generally 
required to be entirely neutral, a somewhat alkaline soap being 
more effective, especially in localities having very hard water ; 
they are less elegantly perfumed, are sold at considerably lower 
prices, and less predominance is given to their fine appearance. 
Nor are laundry soaps generally required to produce so rich a 
lather, and so rapidly, as is demanded of toilet soaps. 

Besides personal preferences are divided between rapidly 
washing or mild, very soluble or economical, cheap or good soaps ; 
in these respects the demand of the customers-must be the guide 
of the manufacturer. 

Toilet Soaps are, or rather should be made, entirely neutral, as 
anv excess of alkali present that is not combined with fat into soap 
attacks the skin while washing and renders it rough. Great care 
is therefore required in making a good grade of toilet soap, that the 
fats employed shall be thoroughly saturated with lye without any 
free alkali being left in the soap when it is finished. Similarly the 
addition of filling, particularly such as carbonate of soda, pear 




The Manufacture of Soaps. 


175 


ash, etc., is much more appropriate for laundry soaps than for 
toilet soaps. The fats employed for making 1 toilet soap must be 
selected with regard to the properties of the soap which they form 
with lye. Thus tallow-soda soap lathers too slowly to be used 
alone; pure cocoanut oil soap lathers very freely, but its continued 
use is not borne by every skin without having a bad effect, and its 
smell is peculiarly unpleasant; grease is too impure, generally, to 
be made into a soap that will preserve its fine perfume and not 
turn rancid in course of time. It will be seen from this that for 
making good toilet soaps special consideration must be given from 
the start to the selections of the fats, to their proper treatment, to 
a process of making them into soap actually free from uncombined 
fat and lye, and to their appearance, color, texture, and perfume 
which are of far greater importance, commercially, in this kind of 
soap than in the grades for ordinal household use. 

The use of some potash in place of some of the soda is of 
quite noticeable advantage in toilet soaps, as it improves the tex¬ 
ture, and also its lathering properties, on account of the greater 
solubility of potash soap. 

For trade in many country places a soap is required which, 
while cheap enough for household purposes, shall also be fairly 
good for personal ablution. This demand is frequently filled by 
soaps which are neither one nor the other, combining the proper¬ 
ties of a somewhat mild laundry soap with those of a rather poor 
toilet soap. 

It will be seen that toilet soaps vary from the soaps for ordi¬ 
nary uses only in the selection of the best materials and more care¬ 
ful manipulation ; but people having a healthy, tough skin, 
frequently can use even a somewhat alkaline soap with immunity, 
and many cheap soaps are sold for toilet purposes which in point 
of purity and mildness are even behind some of the laundry soaps 
in the market. Few people with sensitive skins, and especially 
ladies and children, the use of such articles is often attended with 
irritating effects. 

Shaving Soaps are a class distinct from either of the foregoing. 
They are required not only to furnish a rich lather, but also that 
the latter shall remain on the face for some time without drying ; 
they shall soften the beard without attacking the skin ; they must 
have no unpleasant smell, and yet but little perfume must be used 
in them. These soaps will be specially described in succeeding 
pages. 


Stock for toilet 
soap. 


Potash in toilet 
soap. 


Shaving soap. 


176 


The Manufacture of Soaps. 


Use of textile 
soaps. 


Requirements of 
textile soaps. 


Textile Soaps. Woolen manufacturers, wool washers, worsted 
spinners, silk dyers, calico printers, etc., use considerable quanti¬ 
ties of soap, especially for scouring- and fulling- purposes. Raw 
wool is cleansed of grease and dirt by washing-, potash soap being 
almost universally conceded to answer best for this purpose ; it is 
then treated with oil in order to bring- itintocondition forspinning 
into yarn which is then woven into cloth. The cloth is then ag-ain 
washed or “scoured” in order to remove the oil used in spinning-; 
for this soda or potash soap is used. The fulling process consists 
in spreading soap over the cloth and subjecting the latter to fric¬ 
tion, thereby entwining the fibres of the wool in a manner which 
thickens the cloth ; at the same time the cloth is cleaned by this 
operation. The soap in this case acts as a lubricant. The calico 
printer uses soap to remove certain gums, dextrin, starch, etc., 
applied for printing purposes. In the manufacture of silks soap 
is needed to free the fibre from extraneous matters, and also in 
the process of dyeing. 

Considering the various uses for which soap is employed in 
woolen mills and other textile manufactories, and the various 
degrees of care bestowed on the work by the men entrusted with 
the same, together with prejudice and ignorance, it is not sur¬ 
prising to find that it is by no means agreed what constitutes good 
soaps for the textile industries. What the soapmaker must do 
therefore, is to fqrnish the kind of soap which is demanded, and 
leave it to his customers to decide what they want. Yet it is well 
for the manufacturer to be familiar with the action of different 
soaps in the treatment of cloth, so that he may know where the 
blame belongs when his product should meet with complaint from 
the consumer. 

At the outset it must be understood that really every good 
soap, thoroughly saponified , may be used in textile manufacture, and 
even cold made soaps, filled with silicate, starch, etc., find cus¬ 
tomers, although actually hardly fit for such uses. Some manu¬ 
facturers require a perfectly neutral soap ; but more frequently 
one that is strongly alkaline is preferred. For ordinary woolen 
goods that have not been dyed a somewhat alkaline soap is 
quite suitable, but most colors are readily dimmed by free alkali. 
The natural color of wool is bleached slightly by potash soaps, 
while soda soap—unless very carefully used—is apt'to turn it 
yellowish. A too strong soap, whether made of soda, or potash 


The Manufacture of Soaps. 


179 


cocoanut oil soaps, salt and water allow of an enormous increase, 
beside that by the before-mentioned fillers, so that the manufac¬ 
turer can sell at a very low price, provided he has carte blanche as 
to quality. (The effect of these various editions is further ex¬ 
plained on other pages of this book.) 

SPECIAL PROPERTIES OF THE SOAP. 

Floating Soap. This conists of a hard soap into which air 
bubbles have been incorporated while the soap is still hot. These 
air bubbles are so small as to be almost invisible, and so numerous 
that they largely increase the surface of soap exposed to the water 
when the same is in use. Naturally such soap is more quickly sol¬ 
uble than the same article would be if it were not made to float, 
and regard to this fact should be had in determining on the mate¬ 
rials and process for making this variety. 

Transparent Soap. Transparency is a property which conve} r s 
to the average buyer the impression of purity, although as a fact a 
perfectly pure soap is, under ordinary circumstances, no more 
transparent than is pure tallow or pure butter. By dissolving it in 
alcohol and subsequent evaporating the latter, soap may be made 
transparent. The same result may be, and generally is, brought 
about by the addition of glycerin and sugar dissolved in water, 
with or without the further addition of alcohol. Alcohol and the 
process of recovering it being expensive and troublesome, trans¬ 
parent soaps are mostly made by the addition of much syrup, less 
glycerin, and as little alcohol, if any, as possible under the cir¬ 
cumstances. The glycerin in such soaps is, perhaps, a desirable 
feature, although it causes the soap to attract moisture and become 
wet on the surface in certain weather. The use of some castor oil 
with the other fats tends to cause transparency and to improve the 
texture of the soap, but it slightly reduces its lathering qualities. 

Hard Water Soap. Water containing in solution such com¬ 
pounds as carbonate of lime and magnesia, sulphates of the same, 
or ordinary salt (sea water), is not well adapted for washing, as 
salt water is incapable of dissolving ordinary soap, while the lime 
and magnesia compounds present in most hard waters decompose 
the soap with the formation of insoluble lime and magnesia soaps. 
With such water cocoanut oil soap is the only one capable of doing 
effective work. (Palmnut oil soap is similar to the latter, but 
not made to any extent in this country.) For slightly hard water 


180 


The Manufacture of Soaps. 


rosin soap, or soap containing- a small excess of alkali, are some¬ 
what better adapted than that containing- no rosin. 

“Boiled Down” Soap. Soaps that ha.ve been boiled and “set¬ 
tled,” as will be described hereafter, contain a proportion of water 
more or less great, according to circumstances. The more water a 
soap contains, other things beingequal, the more readily it is solu¬ 
ble, the faster will it wash, and the more of it is wasted in use. 
Where an economical soap is preferred to one that washes rapidly, 
or where the raw material used naturally furnishes a soft product, 
the soap is boiled down so as to reduce the proportion of water. 
Such soap, during the process of boiling down, and through the 
consequent loss of water, becomes of a peculiar consistency which 
does not permit the coloring matter and other impurities present 
to settle to the bottom; these, therefore, remain in the body of the 
mass, and, by a process of crystallization in the hot soap, become 
distributed throughout the mass in vein-like formations, producing 
the “mottle” or “marble” peculiar to boiled down soaps. (If 
Artificial mottle, boiled down too far the mottle will not form, however.) This 

marbled appearance was formerly taken as a guarantee that the 
soap contained but little water, and has therefore come to be more 
or less successfully imitated artifically in soaps containing much 
water. By the loss of water during the boiling down the soap is 
also hardened, and where oils are used which naturally form a 
rather soft and easily soluble soap, such as cotton seed oil and red 
oil, boiling down is often employed. In the case of cotton seed oil 
boiling down also has the additional advantage of preventing the 
yellow spots already referred to. Ordinarily the soaps made in 
this country are nearly all settled soap, so far as they are at all 
made by boiling. 

A peculiarity of boiled down soaps is that they “sweat,” 
i. o., attract moisture in damp weather, owing to the presence 
of foreign salts derived from the liquid on which they are boiled 
down. 

BY WHAT PROCESS SHALL THE SOAP BE MADE? 

The size and facilities of the factory, the prices of its pro¬ 
ducts, and the quality and appearance of the same, demand 
several methods to be employed in different cases. 

Advantages of the The “Cold Process .” The easiest manner of making soap 

consists in simply mixing the melted fat with strong caustic lye 
until a thick mass results which at first becomes heated spoil- 




The Manufacture of Soaps. 


181 


taneously by the chemical reaction taking* place ; upon cooling 
in the frame in the course of a few days the soap is ready. The 
advantages of this “cold process” consist in the first place in 
simplicity and a fine appearance of the finished article while the 
soap is fresh. The gdycerin formed in the process of saponifica¬ 
tion of course remains in the soap (as does in fact everything* 
that g*oes into the mixer). Very small quantities may be 
conveniently made by this process, and at a comparatively small 
expense in time and labor. The disadvantages of the process 
are, however, quite important. It is practically impossible to 
make the soap as perfectly that more or less free alkali and free 
fat do not remain uncombined and mixed in the soap, causing 
harshness by the free alkali, and rancidity after a time and other 
bad features, on account of the free fat; the quantity of lye re¬ 
quired to saponify a given amount of fat cannot even be calculated 
exactly in practice, as both fats and lye var} 7 in composition ; 
but even with an excess of lye used the presence of uncombined 
fat cannot be avoided. Moreover the fats require to be previously 
clarified carefully. Fats containing free fatty acids are entirely 
unsuitable for the cold process. (For further particulars see 
Chapter XIII.) 

The “Half Boiling ” Process. This is a method of making soap 
at a higher temperature than is employed for cold-made soap, but 
without actually boiling. It yields soaps similar to that made by 
the cold process, but permits of somewhat more thorough saponi¬ 
fication (and also, incidentally, of the addition of considerably 
more “filling” matter). 

The Boiling Process. Although this is the process by which 
soap was made in the olden times, it is still the best method at 
this day, notwithstanding the many attempts to improve upon it. 
Only the use of steam instead of an open fire, and the use of ready¬ 
made caustic alkali instead of leaching carbonates with lime in the 
soap factory are to be recorded as essential departures from the 
primitive methods of the ancients ; but open fire is still largely 
employed in other countries,, while the causticizing of carbonates 
by the soap maker is even now practiced in this country to some 
extent. 

For making soap, and especially when large quantities or the 
best qualities are to be made, nothing can be simpler than boiling 
the fats with caustic lye, for the following reasons: The object 
to be attained is to bring every particle of fat into intimate con- 


Disadvantages of 
the cold process. 


Advantages o f 
“half boiling.” 


Advantagesof the 
boiling process. 


182 


The Manufacture of Soaps. 



Boiling necessary 
for perfect sa¬ 
ponification. 


Uivision of boiled 
jfoapfi* 


tact with lye; it is therefore the first requisite that the fats should 
be melted, in order to acquire the necessary fluidity. Next, the 
fat and lye must be very thoroughly mixed with each other, 
which can in no way be done more effectively or more cheaply 
than by increasing the heat—required anyway—to the boiling 
point. The boiling can be continued as long as desired, so that 
the soap maker has perfect control over the operation ; this he 
cannot have in the cold process, and the result is that only by 
boiling every trace of fat can be saponified. Then, again, it is 
only by various operations made possible by boiling that the gly¬ 
cerin formed in the course of saponification, the excess of lye, 
and numerous impurities contained in the fats and in the lye can 
be removed ; the consequence of this is that well boiled soaps, 
made neutral and freed from foreign matter, wash away less rap¬ 
idly than cold made or half boiled soaps, and do not become 
rancid in time by the presence of free fat. 

The boiled soaps, as usually made in this country, may be 
divided into two classes: “Settled” and “Boiled Down” soaps, 
besides the “Run” soaps, which are hardly made any more, 
however, at the present time. The settled soaps, which are those 
produced in the greatest quantities, are made by allowing the 
hot soap, while rather thin, to settle in the kettle, so that the 
impurities, the foreign salts, and the excess of lye and water, to¬ 
gether with some of the soap, form a dark precipitate called 
“nigre,” from which the pure soap is drawn off. Such soaps 
contain a greater proportion of water than “boiled down” soaps, 
which have already been briefly described on page 180. “Run” 
soaps were made by simply saponifying the fat by boiling with 
lye, and framing the mass obtained with such liberal allowance 
of water and filling as was desired. 

[Since the first edition of this treatise the process of boiling 
soap under pressure—with the object of saving time and, as was 
claimed, increasing the yield—made its appearance once more, 
but found no favor. We mention it here only for the purpose of 
adding to it a few words on a rather interesting patent granted 
to C. Polony, of Vienna, who uses the boiling under pressure for 
a novel purpose: He slowly heats the fats in a closed vessel with 
ammonia (sp. gr. 0.96 to 0.875), gradually raising the pressure 
to 5 atmospheres ; ammonia soap is formed which is then grained 
with salt solution while again boiling in the closed vessel ; the 
salt (chloride of soda) changes the ammonia soap into a soda soap, 


The Manufacture of Soaps. 


183 


while in the waste lye are found chloride of ammonia and gly¬ 
cerin ; from the former the ammonia is regained by distillation 
with lime, to be used again in the next batch. The advantages 
as claimed by the inventor are the doing away with the necess¬ 
ity of using caustic, a better quality of glycerin, and a saving in 
time (?). The saponification with ammonia takes place under 
these circumstances owing to the fact that under pressure the 
vapor of ammonia separates the fatty acids from the glycerin and 
the former then combine with the ammonia]. 

Milled Soap. The mechanical process of milling has for its Advantageaof 
object the forming* of cakes of soap which will not shrink with age, 
retain a fine appearance, an even texture, and are finely per¬ 
fumed while the soap is cold, so that a minimum of perfume 
only is lost by evaporation. Milled soaps contain only a small 
percentage of water, as they must be thoroughly dried before 
being treated by the machinery described on the preceding 
pages, and they consequently preserve their original shape 
indefinitely. A well dried, neutral, boiled soap may be mixed 
with colors and perfumed and be worked into the finest and 
best articles for toilet purposes. By this process, however, cold Cold made soap 
made soaps are frequently milled also, in order to take advantage for milling, 
of the popular favor in which milled soaps are held, although in 
this case milling is of little practical benefit to the soap, except 
perhaps in so much as it becomes a little milder by being exposed 
to the air and by the repeated handling. An ordinary cold made 
soap is amorphous in structure, while milled soap shows a grainy 
or fibrous formation, in consequence of which the ends of the 
cakes, after pressing, have a different appearance than the cakes 
of either cold made or ordinary boiled soap. At present the mill¬ 
ing process is confined to the manufacture of toilet soap, but in 
view of the constantly improving character of laundry soaps, and 
the improved machinery likely to become popular some time in 
the future, it would not seem improbable that milled laundry soap 
is yet among the possibilities. 

REMELTED SOAP. 

For making toilet soap from stock soaps, but more often for 
working up scraps of soap without boiling them over, remelting 
may be resorted to. For the manufacture of toilet soap the process 
of remelting is mostly confined to England, where the soap manu¬ 
facturer furnishes a well boiled soap to the perfumer, who colors, 


184 


The Manufacture of Soaps. 


perfumes and works it over into cakes of toilet soap by remelting-. 
In this country toilet soap is g-enerally made by milling* or by the 
cold and half boiling* process. But for working- over the scraps of 
soap, remelting is the most convenient and economical way. The 
cold process permits of hardly any other convenient means of 
utilizing scraps, while the reboiling of scraps would cause the 
loss of the filling which would go into the waste lye, and of the 
perfume. 






CHAPTER VII. 


Settled Soaps. 


The settled soaps are those made, brie fly stated, by boiling' 
the fats, oils, and rosin with lye until thoroughly saponified, se¬ 
parating and drawing off the waste lye, “ strengthening ” and 
washing with a change of lye, and subsequently thinning the 
soap out with water, whereby the excess of alkali and other im¬ 
purities are settled to the bottom of the kettle, as more fully 
described hereafter. The last mentioned operation is technically 
termed “pitching” or “settling.” This is the most—not to say 
the only—practical process for making a thoroughly saponified 
and at the same time perfectly neutral piece of soap. Even a 
soap that has been boiled down without previously settling it (a 
process by which, for instance, the true Marbled Castile is made) 
always contains some free caustic alkali. 

The settled soap* may be conveniently divided into those 
containing rosin (yellow soaps), and those not containing it 
(mostly white soaps). We will first describe the former. 

ROSIN SOAP. 

The settled rosin soaps are made either of tallow and rosin, 
or grease, stearin, palm oil, cocoanut oil, cotton seed oil, etc., 
may be substituted in place of part or all of the tallow. 

For soaps containing a large proportion of rosin, fats rich in 
stearin are best suited, while the softer fats and oils are more 
suitable for soap in which little or no rosin is employed. This 
adaptability of the different fats rests on the solid consistency and 
comparatively small solubility of the soap formed by the combina¬ 
tion of stearin and soda. Rosin softens such soap and makes it 


Definition of set¬ 
tled soaps. 


Selection of stock. 




186 


Settled Soaps. 


Settling or clari¬ 
fying the stock. 


more soluble. On the other hand, the softer fats and oils, contain¬ 
ing- less stearin, form soaps, which are naturally soft and easily 
soluble ; they are consequently adapted for use in connection with 
much rosin only when a “boiled down” soap is to be made, in 
w T hich case the decrease in the quantity of water present counter¬ 
acts the softening- effect of the rosin. 

Cocoanut oil, used tog-ether with other fats in a rosin soap, 
increases the solubility still further, but the soap will be harder 
than a tallow-rosin soap that had been made equally soluble by 
the use of a larg-e proportion of rosin. It will also lather more 
freely. 

The better grades of settled rosin soap are made of fats and 
rosin in the proportion of about 35 lbs. of the latter to 100 lbs. 
of fat, and mostly with the addition (in the crutcher) of about 
6 to 8 per cent of a strong- solution of carbonate of soda to the 
finished soap, for the purpose of hardening it and increasing its 
detergent properties. 

Cheaper varieties are made by using ordinary grease in 
place of the tallow or the other fats and oils used; also by in¬ 
creasing the proportion of rosin (up to 100 per cent and more of 
the fat used), and by “filling” with silicate of soda, talc, silex, 
mineral soap stock, etc. 

Taking a soap of tallow and 35 per cent rosin as the basis 
for a description, the process of manufacture is conducted as 
follows: 


Saponification of the Fat. 

The clear fat is drawn from the settling tank into the clean 
kettle; or, in the absence of a settling tank, and if there is no 
“nigre” in the kettle, the tallow is run into the latter as it is 
melted out of the barrels, and clarified by boiling it on water to 
which some salt and some alum have been added. The dirty 
water is then run away after a short rest. The use of a settling 
tank is always to be recommended, as it will permit of examin¬ 
ing the fat for adulterations, many of which settle out while at 
rest; and also because the clarification by boiling on salt water 
can be conducted in it, while the kettle is otherwise occupied. It 
will also be well to take notice of the amount of lye absorbed by 
the fat, and should a certain lot of fat use noticeably less lye 
than usual it will be advisable to examine it for unsaponifiable 
admixtures. 


Settled Soaps. 


187 


The salt has no other effect in this operation of clarifying’ 
than to cause the dirty water to settle rapidly after boiling - , in 
consequence of the increased gravity communicated to it by the 
dissolved salt. When the water has been drawn off, the clear 
fat is ready for saponification in the same manner as if it had been 
drawn from the settling - tank. 

Alum may be used, tog-ether with the salt, to remove gluey 
impurities contained in much of the greases and tallow found in 
the market. 

The same preliminary treatment of the fats is indicated when 
lard, stearin, grease, cocoanut oil, &c., are to be clarified; many 
impurities are thereby removed which it is difficult, or even quite 
impossible, to eliminate from the mass after saponification. 

A different method of clarification consists in using strong 
lye instead of salt water, and only working the contents well 
through with steam, without heating more than necessary to 
accomplish this; then applying just enough steam to separate 
the dirty lye well from the fats, and drawing it off. 

The clear fat is next saponified, or “killed,” as it is termed, 
by running lye into the kettle and turning on open steam, or 
both the open and closed steam. “Tallow,” it ufeed to be said 
when our commercial caustic was not of as high grade as it may 
now be had, “requires weak lye at first, as it combines with 
strong lye only after it has been already partly saponified.’ 1 
The lye was, therefore, run in at a strength of 8 to 10 B. at 
first. 

But this behavior was due to the foreign salts in the caus¬ 
tic, and if the lye is made by dissolving caustic soda of high 
grade in water, it might be used much stronger from the start, 
and would still combine with the tallow; only the resulting mass 
would be too thick to boil freely; so weaker lye is either used, 
or stronger lye and water are run into the kettle together. 

Cocoanut oil combines readily with strong lye, and in doing 
so draws the tallow into the combination if both are saponified 
together. If, therefore, the fat consists of both, tallow and 
cocoanut oil mixed, instead of tallow alone, the lye—even if 
made from the lower grades of caustic—may be used stronger 
from the beginning in the ratio as the proportion of cocoanut oil 
to tallow 7 is larger. Palm oil, stearin, and grease are similar to 
tallow in this respect; cocoanut oil only finds a counterpart in 
palmnut oil and in free fatty acids. 


Another method 
of clarifying. 


Strength of lye to 
begin saponifi¬ 
cation. 


I 


188 Settled Soaps. 

Too weak lye only adds unnecessary water to the boil and 

retards the chemical combination. When, on the other hand, 

* 

the lye used is made of low grade (say 60%) caustic and applied 
too strong at any stage of the saponification, the partly formed 
soap is unable to remain dissolved in it; it then coagulates or 
“opens” (so that the lye can be observed to separate from a sam¬ 
ple taken on the paddle or trowel) thereby preventing the proper 
action of the lye on all the particles of fat. If this condition 
should set in at any time during this operation, weaker lye must 
be added until the mass “closes” again. But if the lye was 
made of high grade (say 70%) caustic, then the soap will either 
not open at all, or close by itself after a few minutes’ boiling, 
should the lye be too strong at any time. 

The lye used in this operation may be made by dissolving 
in water caustic of 60% or of 70%, or of any other grade desired, 
according as convenience of working and cost of the caustic may 
dictate. The action of lye of different grades in this respect has 
been explained above, and also on pages 73-76, and we need 

1 / the e:ir " therefore merely repeat more especially that the carbonate of 

soda in all lower grades of caustic does not combine with neutral 
fats, and will'therefore be lost by running away the waste lye 
afterwards, unless precautions are taken to absorb it previously 
to running away the waste lye, by the addition of some free 
fatty acid, or rosin. This utilization of the carbonate can only 
be effected, however, when there is no more caustic alkali present 
in the kettle, as otherwise the rosin or free fatty acids would 
combine with the latter in preference to the carbonate. 

The lye is run into the kettle in a steady stream, and under 
constant boiling. The presence at any time of a large surplus 
of lye in the kettle only retards the process of saponification, 
but a lack of lye at any time must also be guarded against, as it 
would cause “bunching” (a thickening up of the partly formed 
soap). The \ye is therefore added only about as fast as the fat 
is able to absorb it, and not fast enough to disturb the even 
ebullition of the mass. 

“Bunching.” When working with a large kettle, in which “bunching” 

would be especially troublesome, requiring hours of work and 
boiling to overcome, it is advisable to run in lye and fat together 
from the start, thereby saving time and reducing the risk of 
bunching at the same time. This is especially necessary if the 
fats contain free fatty acids in large proportion, which combine 


Settled Soaps. 


189 


very quickly with lye, and are thus particularly liable to cause 
the trouble mentioned. 

Should bunching of the soap take place, very strong lye or 
salt water must be run in, the steam turned on full, and the con¬ 
tents well worked through until they are brought back to the 
normal state. In the case of a small kettle this process may be 
assisted by vigorous crutching. 

To regulate the strength of lye, strong lye and water may 
be run in together, gradually decreasing the proportion of water. 
(A convenient arrangement for this purpose may be found under 
the description of the lye tank, on page 94.) 

The saponification or “killing” of the grease is most ad¬ 
vantageously performed by boiling slowly with open steam, 
which, by the pressure with which it issues from the perforated 
pipe, causes a brisk movement in the contents of the kettle. 
When the kettle has both open and closed steam, satisfactory 
results may be obtiined by using both; when boiling with closed 
steam great care is necessary, however, as the steam pipe remains 
hot for some time after shutting off the steam, and a boiling 
over might be impossible to prevent if once started with a hot 
closed coil. 

The heat developed spontaneously by the combination of the 
materials taking place is often sufficient to cause boiling over 
even when all steam has been shut off; it is therefore often ad¬ 
visable to have water or salt water handy to sprinkle over the 
soap in case of necessity. In all operations of boiling it must be 
remembered that the open steam adds its condensing water to 
the mass and causes a strong agitation in the contents of the 
kettle; the closed steam, on the other hand, causes a slower, 
even ebullition, and removes water from the kettle by eva¬ 
poration. 

This operation of saponifying the fat (also called “First 
Change”) is considered complete when the soap formed will not 
absorb any more lye, and, after boiling for a reasonable time 
without the addition of more lye, indicates by the peculiar 
“sharp” alkaline taste that the last lye added remains uncom¬ 
bined in the kettle (the soap has surplus strength). At this 
stage the mass begins to be clear; a small sample taken on a 
piece of glass is transparent and remains so until it cools off. 
Pressed between the fingers it should have a good body and not 
be smeary; a sample taken on the thumb and pressed in the palm 


Use of open and 
closed steam.' 


End o f first 
change. 


190 


Settled Soaps. 


of the hand by sliding- the thumb over it, must curl into a rather 
dry shaving. 

When the proper signs mentioned are absent, although the 
soap has a sharp taste, it indicates the presence of unsaponified 
fat, owing to the lye used having been too strong, so that it 
could not act properly on the fat. The addition of weak lye, or 
even water, or boiling a little longer, will then be required to 
cause the soap to absorb more lye. 

The total quantity of lye required for the saponification is 
roughly estimated at 100 lbs. lye of 20° B. to every ICO lbs. of 
stock. Cocoanut oil requires a little more lye than ordinary fats. 
The exact quantity of lye necessary for saponifying a fat is not 
required to be calculated in making soap by boiling, and is there¬ 
fore made the subject of some special remarks in another chapter 
of this treatise. 

It is a not uncommon error to believe that when the soap 
shows some sharpness after the boiling has continued for a few 
minutes without the addition of more lye, the fat must be per¬ 
fectly saponified. This assumption, however, is often far from 
the truth, for even after the soap has been again boiled on fresh 
lye, it very frequently still contains unsaponified fat. Indeed, 
many—not to say most—ordinary soaps on the market contain 
free fat from this cause. A thorough saponification is only 
effected by prolonged boiling with sufficient l} T e of proper strength 
to permit combination. 


Graining. 

When the saponification has proceeded until the before men¬ 
tioned signs indicate that the soap has been well formed, the 
next step is to remove from it the waste lye, that is to sa} T the 
superfluous water, the foreign salts that were contained in the 
lye, (notably carbonate of soda) and the glycerin formed during 
the process of saponification. This removal is effected by add¬ 
ing salt, or salt soaked in water, or—better yet—a saturated so¬ 
lution of the same in water, or strong lye (30 to 40° B,) to the 
boiling mass. 

The waste lye, on taking up the salt, or the excess of caustic 
as the case may be, becomes unable to hold the soap in solution, 
and at the same time it withdraws water from the soap; as a con¬ 
sequence the latter rises to the top of the mass in the kettle, and 
the waste lye with the dissolved salt, glycerin and various im- 



Settled Soaps. 


191 


purities settles to the bottom. About 6 to 8 per cent of salt 
(calculated on the weight of fat used) is required for this pur¬ 
pose, the quantity depending on the amount of superfluous water 
present and on the kind of fats used. 

A pure tallow soap will thus be separated from the waste 
lye when the latter contains enough salt to indicate 12 to 14 : B. 
on the hydrometer. Cocoanut oil soap remains soluble in the 
waste lye until the latter is raised by salt to above 24-26° B. 

If salt is used it is preferably dissolved in water before add- 
• • 

ing it, as some of it is otherwise liable to remain undissolved in 
the soap and cause trouble afterwards. This is especially so if 
the soap is of a tough consistency, such as results when a good 
tallow is boiled with strong lye made from high grade caustic; 
in such cases, when dry salt was used in the first change, it has 
even happened that it was found still undissolved in the finished 
soap in the frames. 

The soap, boiling well while receiving this addition, will 
“open,” that is to say, it will coagulate slightly, and the lye sepa¬ 
rates from a sample taken on the paddle. When it is observed that 
the soap begins to open, no more salt or brine is required ; the 
open steam is turned off, and boiling is continued on closed steam 
only, until by evaporation the soap is deprived of enough water, 
and the waste lye has become concentrated so far, that it sepa¬ 
rates clear and thin from a sample of soap taken on the paddle 
(or trowel used in its place in some factories). The closed steam 
is then also turned off, and the soap is allowed to rest for say 
four or five hours, in order to let the waste lye settle. 

The effect of the salt or brine here described mav also be 

•/ 

brought about, as stated before, by using strong lye instead. 
Salt is ordinarily used merely for the sake of economy, as the 
waste lye is charged with many impurities, and therefore run 
away without further use (unless worked up for the recovery of 
glycerin). But the use of strong lye has the advantage of keep¬ 
ing the soap free from salt, which but too often causes soap to be 
“cracky” in the frames, unless it has been very thoroughly re¬ 
moved in pitching. When lye is used instead of salt the alkaline 
strength it contains may afterwards be utilized in making a 
lower grade of soap. 

Cocoanut oil soap is difficult to grain on salt, of which a 
large quantity would be required to separate it from the waste 
lye; consequently, when a large proportion of cocoanut oil is 


The use of lye in¬ 
stead of salt for 
graining. 


192 


Settled Soaps. 


Saving the soap 
from the waste 
lye. 


saponified together with other fats, a different method of work¬ 
ing is generally adopted, as will be explained hereafter. 

It sometimes occurs—with the use of stock of poor qual¬ 
ity—that the soap refuses to open on the addition of salt. This 
may then be remedied by allowing it to cool off somewhat, and 
if it should thereafter become weak in alkali, adding a little more 
lye, when it will generally separate without further trouble. It 
may be advisable to assist the process in this case by means of 
crutching. (See also under “Grease,” page 46, on this subject). 
Sometimes soap will not open on dry salt for the reason that 
water is lacking to dissolve it, in which case brine is necessary 
for the purpose. Some soaps naturally appear thin (cotton seed 
oil soap, for instance) even if they contain but little water, so that 
brine may sometimes be necessary, instead of salt, notwithstand¬ 
ing the fact that the soap has a thin appearance. 

The waste lye, after sufficient rest, is drawn off into a tank 
in which it is allowed to cool, before running it away. Any 
soap which it may have held in solution while still hot will then 
separate and may be regained, whereupon the clear waste lye is 
run away (or worked up for glycerin ). A dirty precipitate will 
collect on the bottom of this tank, and must be removed from 
time to time, as it is of no value. This is most easily effected by 
connecting the tank with the steam boiler whenever the latter is 
“blown off,” letting the hot water from the boiler run through 
the tank, thus washing away the precipitate which is quite diffi¬ 
cult to remove in any other manner. 


The Rosin Change. 

The waste lye having been drawn off, the rosin is next 
saponified by boiling it, together with the soap, on additional 
lye. Fresh lye is first run into the kettle, at a strength of from 
18 to 20° B , and in sufficient quantity to at least stand high 
enough in the kettle to cover the closed steam pipe, in order to 
prevent as much as possible the sticking of the rosin to the hot 
pipes. Both open and closed steam are then turned on and, after 
boiling the soap alone for a short time, till it forms a some¬ 
what grainy mass, the rosin is shoveled in, having been previously 
reduced to pieces of about the size of an orange. 

The lye is used at say 18° B. because at this strength it 
combines readily with rosin. Weaker ly^e would be apt to cause 
frothing of the soap, would be a waste of kettle room, and would 


Settled Soaps. 


193 


interfere with the free working- of the contents, as during- the 
saponification of the rosin the soap must be kept “ open ” by 
having- an excess of sufficiently strong- lye in the kettle at first, 
and towards the end of the operation by adding- salt. 

The closed steam is used during- this chang-e to promote an 
even, regular boiling; the open steam serves to keep the rosin 
from the closed coil. 

The rosin used may be of light or dark color, according to 
the grade selected. Of course the darker the rosin used, the 
more highly will it color the soap, as only part of the coloring 
matter can be removed by boiling on lve and subsequent settling. 

The rosin combines almost instantly with the ly^e, which 
must be continually run in (at the strength above mentioned) 
while the rosin is being gradually added, so as to keep the soap 
open by the excess of strong lye always present in the first 
stages of this change. When nearly all the rosin has been 
shoveled in, the supply of lye is cut off, and some salt or brine is 
added into the kettle to keep the soap open, while the last 
strength of lye is absorbed by adding the remainder of the rosin. 

The object of having the soap open on the rosin change is 
two-fold. In the first place, it promotes easy working in the 
kettles and prevents the rosin from going to the bottom too 
readily; secondly, it helps to discharge more of the coloring 
matter of the rosin. The combination of the rosin (unlike that 
of neutral fats) with the lye is not in the least distributed or re¬ 
tarded when the soap is open. 

All the rosin having been added and saponified, the soap be¬ 
ing open on salt, and when the lye runs thin and clear from a 
sample on a trowel, the steam is turned off and the soap allowed 
to rest for about five or six hours, to settle the waste lye. As 
the latter is run away it should have no caustic strength, or at 
least but very little; a slight sharpness here aids to discharge 
more of the color of the soap, as does also the presence of some 
carbonate of soda in the lye. When the lye is well separated, 
draw it off and run it into a tank as before, to regain the soap 
which it holds in solution while hot. After cooling in this tank 
the soap is taken off and the clear lye is then run away. 

[For a simplified process of making this soap, strong lye 
at 20° to 25° B. may be used instead of salt to keep the soap 
open as described auove. This lye, after separating by rest, is 
then saved for the strength it contains, and the soap is thinned 


simplified pro] 
cess. 


194 


Settled Soaps. 


by boiling- on a little water and open steam, and “settled,” as 
described hereafter. Made in this way, the soap is darker and 
the fat less thoroughly saponified than when the more elaborate 
process, as here described, is employed.] 

Strengthening Change. 

The waste lye from the rosin change being run off, the soap 
is boiled again on lye, in order to saponify the last particles of 
fat and rosin still present and to wash out as much of the re¬ 
maining color, salt, and other impurities as possible. The salt, 
especially, must be removed, as its presence disturbs the opera¬ 
tion of settling, and later on also the framing. This process, 
called “strengthening,” may be carried out as follows: 

Weak lye, of say 6-10° B. (according to contents of water 
still in the soap and to steam used, closed or open), is run into 
the kettle, enough to cover, as before, the steam coils, so that 
boiling may proceed quietly, and that the rosin which may still 
adhere to the coil may be saponified. Closed steam is turned on, 
and the soap boiled slowly. The strength of this lye is reg¬ 
ulated on the principle that while on one hand no unnecessary 
water should be introduced, it is on the other hand in a close 
condition of the soap that the lye can best reach all the particles 
of unsaponified stock. As the alkaline strength is absorbed 
more lye of the same strength is added, and occasionally the 
open steam turned on for a few minutes to work the contents of 
the kettle through, and to remove any rosin which might still 
adhere to the coil. Enough lye must be added to give the soap 
good sharpness and to cause it to open to a very soft and large 
grain, in which condition it most readily drops the impurities 
and is most easily drawn together with water afterwards. If 
grained too far, by too strong lye or by too prolonged boiling, 
much water is required later in finishing, causing an excessively 
large “nigre” and trouble in framing, as will be more fully des¬ 
cribed in the succeeding pages. When opened, as stated, the 
materials should have become well saponified, and a sample, 
when pressed between the fingers, forms comparatively dry 
scales which must not be smeary. Steam is turned off and the 
lye given time to settle After sufficient rest the lye—which 
may even be weak enough to have a little soap dissolved in it 
without detriment, especially when very dark colored stock has 
been used—is drawn off and saved for its strength which it still 


Settled Soaps. 


195 


contains, On cooling-, any soap that it may have held in solu¬ 
tion may also be reg-ained. 

A different proceeding: may be adopted, instead of the An extra change, 
strengthening- change here described, by first making an extra 
change in the following manner: 

The waste lye from the rosin change being drawn off, open 
steam is turned on and weak lye, or even water, run into the 
kettle. Boiling and the addition of weak lye are continued un¬ 
til the soap becomes close and thin, and tastes slightly sharp. 

Then it is grained by the addition of brine, and boiled on close 
steam until a good curd is formed. Then, after sufficient rest, 
the waste lye is run away and the soap closed again by the ad¬ 
dition of water, under constant boiling, until it is clear and 
smooth. Bye of 10 to 15° B. is then run in and boiling con¬ 
tinued, on both open and closed steam, till the soap opens again 
and the lye begins to separate from the soap. Boiling is then 
continued on closed steam alone, till the soap forms a soft, 
round curd, and the froth formed at first begins to disappear. 

After resting for some hours the lye is drawn off and saved, as 
already described. 

•“Fi NI s HIN g” or “Settling.” 

This operation, also known as “pitching” or “fitting,” pro¬ 
gresses most favorably in large batches, as it depends greatly on 
the length of time during which the soap retains its heat. The 
object is to remove the free alkali, water, salt and other impuri¬ 
ties that still remain, such as the insoluble soaps formed by the 
combination of small portions of the fat with various impurities 
of the alkali, as lime, iron, etc. It is carried out as follows: 

The lye from the strengthening change being drawn off, the 
open steam is turned on slowly to warm the soap, and a little 
water is then run into the kettle. Boiling is thus continued with 
open steam, or with both open and closed steam, until the soap 
is quite tough and “ close,” and a sample slides from the paddle, 
held slanting, in large flakes, which adhere tenaciously to the 
paddle, so that on dropping from the latter the part still adher¬ 
ing draws back like an elastic band. The soap in the kettle 
must look bright and shiny, and should have but little sharpness. 

It will rise in the kettle and should be made to swell up as high 
as possible, which will facilitate the dropping of the “ nigre.” 

Only so much water must at first be added that the soap 


196 


Settled Soaps. 


does not assume the appearance here described too quickly, so 
that the water may be well boiled through before the operation 
is finished, and may be distributed evenly throughout the mass. 

If at the beginning of the operation it should be found that 
the soap thickens, it is either lacking in water and then will be 
sharp in taste, or it is weak in consequence of a deficient supply 
of lye. Accordingly water or weak lye must then at once be 
added, in order to bring the soap into proper consistency and 
sharpness. 

When the soap has been raised as high in the kettle as pos¬ 
sible the latter is covered up to keep in the heat, and the closed 
steam is turned on for half an hour longer, when it is also turned 
off; there is little danger of boiling over if properly managed, 
but it may be well to watch the kettle until the steam is turned 
off. The soap is now’ allowed to rest for a day (when it may be 
uncovered if the weather is warm, to cool off more rapidly if the 
saving of time is an object), or it remains covered to settle as 
long as possible. According to the size of the kettle and its con¬ 
struction, and to the w’eather, the cooling will require from two 
days to a week. The more time can be allowed for settling the 
more thoroughly can the operation be carried out. 


Genekal Remarks. 


Simplified 

ods. 


In the foregoing pages has been described the most usual 
process for boiling settled rosin soap; but different plans are 
sometimes adopted to suit different circumstances. For instance, 
the rosin may be added at once when the tallow has been saponi¬ 
fied, without first graining on salt. Or, on the rosin change, 
the soap may be kept open on alkaline strength at first, without 
using salt for the purpose, and finally enough rosin added care¬ 
fully to take up nearly all this strength, so that the soap boils 
in a close condition similar to that in the finishing boil already 
described. It may then be settled at once, without a separate 
strengthening change, and the boiling is thus simplified, but, 
of course, at the expense of the quality of the product. 

Another simplified process consists in boiling fat and rosin 
together on brine, in order to discharge as much of the color as 
possible, and then saponifying with lye at from 15—25° B., so 
that a little sharpness is left at the end of the operation. In 
this condition the soap is left to settle. 

Or again, the fat and rosin may be saponified with just 


Settled Soaps. 


197 


enough lye to make the soap perfectly neutral, cooled as if for 
settling, and framed in the ordinary manner. (This would of 
course not be a “settled ” soap.) 

Several other varieties of these simplified processes might be 
mentioned, but since they naturally do not produce as thorough¬ 
ly saponified and clean soap as is made by the more extended 
method described in the preceding pages, it is not necessary to 
go into further details on this line. 

As has been said before, rosin combines readily with car¬ 
bonated lye; it seems, however, that the soap formed in doing 
so is softer than that made with caustic lye, and the carbonic 
acid set free during saponification throughout the mass is a 
great inconvenience. 


Framing. 


When the soap in the kettle has become cooled down to 
about 140° F. in warm weather, or 150° F. if the weather is cold, 
framing of the clear soap may be begun. 

At the bottom of the kettle will be found a dark colored 
soap like mass, called the “nigre,” which amounts to about one 
quarter—more or less—of the whole. Above this is found the 
clear soap. (The utilization of the nigre will be treated on 
hereafter.) 

The clear soap, if run hot into the frames without filling, 
and left there to cool, will solidify in wave-like formations, 
causing an appearance not unlike the grain of wood, which they 
resemble also in that the bars of soap warp slightly in the direc¬ 
tion of the waves on drying. The cause of this is the crystalli¬ 
zation of the soap formed by the stearin and soda, from the olein 
soap. The soap framed in this manner would, however, remain 
soft until it dries considerably, and for the purpose of hardening 
as well as to prevent it from warping too much on drying, and 
to increase its detergent properties, a strong solution of carbon¬ 
ate of soda in water is crutched into the soap before running it 
into the frames. In England, where a perfectly neutral soap for 
all purposes is made so much of (and to a small extent also in 
this country) the clear soap is framed without any addition and 
known there as “Primrose” soap. 

The framing of the soap is generally done as follows: 

The carbonate of soda required is melted, either sal soda or 
soda ash being employed. Sal soda is melted by the application 


Unfilled soap. 


Sal soda filling'. 


198 


Settled Soaps. 


Soda ash. 


Manner of 
ing. 


of open and closed steam, to be of a strength of 33-34° B. while 
hot (which will be equal to 34-36° when cold). If it is to be used 
cold it should be melted the evening before, so as to let the sedi¬ 
ment settle over night and cool off. Instead of sal soda, which 
was formerly the purestcommercial form of alkali, many factories 
now use a very pure grade of soda ash, or what is known as 
“58% pure alkali,” of which a sufficient quantity is dissolved in 
enough water to be of the desired strength, as above, 
fram- The clear soap is pumped out of the kettle into a vessel which 
is somewhat larger than the crutcher, and placed directly above 
the latter, so that the soap will run from it into the crutcher by 
its own weight on opening the valve. The object of this vessel 
is to permit of continuous pumping while one frame of soap is 
being crutched, whereby not only time is saved, but the danger 
of the soap setting in the pipes and choking them is also averted. 
(Towards the end care must be taken not to draw any part of the 
nigre into the crutcher, as the nigre softens the soap, causes 
spots, and interferes with the soap taking the filling.) When 
soap enough to nearly fill the frame has been run into the 
crutcher, the machine is started up, and from 6 to 9% of the soda 
solution added at once. The crutcher must be sufficiently filled 
to prevent the soap from catching air as it falls over the rim of 
the inner cylinder, as otherwise it will become frothy. The soap 
at first thickens, but as the machine gradually runs faster and 
thoroughly mixes the contents, the soap becomes perfectly smooth 
and bright. The crutching for each frame does not require over 
five minutes, and as the soap cools off during this time, advant¬ 
age is taken of this fact to add the perfume just long enough be¬ 
fore running the soap into the frame to insure its thorough 
mixing; this avoids, as far as possible, the evaporation of the 
perfume. (See, also, the chapter on perfuming soaps). A sam¬ 
ple taken out of the crutcher, when cooled off, must be quite 
solid, and on cutting with a knife it must not be smeary. A 
clean trowel sunk into the hot soap, until it becomes heated, and 
then withdrawn, must have the soap closely adhering to it 
and thus show that it is in a “close” condition. If these con¬ 
ditions are properly fulfilled, the soap is at once run into the 
frame and will be a good marketable product when cut and 
pressed; nor will it effloresce on aging. 

The exact amount of soda solution which the soap will take 
without trouble may be determined by trying say 6 per cent at 


Settled Soaps. 


199 


first and crutching; if the soap assumes the smooth appearance, 
etc., described, the quantity added is sufficient, but if a sample 
taken out does not retain this appearance on cooling', then more 
must be added, till the soap, when cold, is satisfactory. 

If the soap fails to thicken after the soda solution has been 
added, or to become perfectly smooth and close, but on the con¬ 
trary opens, it is an indication that either the strengthening' 
change or the thinning out in the kettle for settling was not 
properly managed. If the soap does not adhere to the hot trowel, 
but leaves the latter clean and bright, it indicates also that the 
soap is too short, i. e ., has been separated, and is not in proper 
condition for framing. The only remed} r in this case is to grain 
the whole boil again and make a new settle, for if framed in 
that condition it would drop part of the soda filling in the frame, 
be full of cracks, and become covered with efflorescence on dry¬ 
ing. Only soap which is very nearly or quite neutral can be filled pro¬ 
perly, and if the soap had been grained too far in the strength¬ 
ening change, so that the lye could not settle out well, and too 
much water was required for thinning in consequence, the soap 
will not settle properly, will contain too much water, and will 
not be sufficiently neutral to take the filling readily. 

The proper temperature for framing is a matter of importance 
in this soap (as in most others), and should therefore be regul-. 
ated by warming or heating the soda solution in the ratio as the 
soap remaining in the kettle cools off, while the first part is be¬ 
ing framed. While the soap is still at about 140° F. (according 
to circumstances), the solution is used at about the same tem¬ 
perature, but with too cold soap it may be necessary to heat the 
filling, even to boiling. If framed too hot, the soap will be 
cracky on drying. Soap containing much rosin, or much 
water, must be framed at a lower temperature than the soap here 
described, say at 130° F. If for any reason the soap arrives too 
hot in the crutcher, cold water is circulated in the steam jacket 
of the machine. 

When the average temperature of the soap and soda solution 
together is too cold for framing, the mass will assume a dull ap¬ 
pearance in the crutcher, remain soft, and is prone to become 
frothy by the action of the machine. The crutcher must then 
be stopped and covered, and steam admitted to the jacket until 
the mixture is warmed up properly. For the next frame the fill¬ 
ing must then be heated. 


Temperature i n 
filling’. 


200 


Settled Soaps. 


Conditions gov¬ 
erning amount 
of filling. 


Evaporated s a 1 
soda. 


Starch. 


Regarding- the amount of soda ash or sal soda to be used in 
framing, this has been stated above at 6 to 9 per cent of the 
weight of the soap, which is the proportion generally used, and 
the mode of preparing it has also been described. However, 
these statements are subject to the following qualifications : 

One reason why the correct proportion varies is that the 
soap may not have been finished perfectly neutral, or it may 
have retained some traces of salt. In these cases the soap 
will not take as much filling as a properly finished soap would 
stand without trouble. 

Another thing to be considered is the quality of the carbon¬ 
ate of soda used in preparing the solution. It is obvious that it 
cannot be immaterial whether the carbonate is pure or otherwise. 
Some soda ash contains as high as 20 per cent of foreign salts, 
while sal soda and 58 per cent of alkali are very much purer. 
The foreign salts do not have the same effect on the soap as the 
actual carbonate of soda, and more of the impure alkali would 
therefore be required to be the equivalent of the pure article. 
But on the other hand, the foreign salts in the lower grades of 
soda may act as a disturbing element (especially when fram¬ 
ing rather warm), for they will naturally exert a similar in¬ 
fluence in the soda solution as if they were present in the soap, 
and the consequence of this may very easily be cracky soap. The 
pure grades of alkali are therefore preferably employed in 
in filling. (See App. Note 15). 

When too much water is present (either from having thinned 
out the soap too far in the finishing boil, or because the soap had 
been grained too strongly in the previous change), part of the 
ordinary sal soda may be substituted by “evaporated ” sal soda, 
or “concentrated” sal soda, which is a carbonate having much 
less water in its composition than is contained in the ordinary 
article. This “evaporated” carbonate attracts the superfluous 
moisture in the soap, and is used by stirring it dry into the hot sal 
soda solution. The amount of it to be used must be judged by 
the appearance of the soap in the crutcher. One pound of it is 
equivalent in alkali to 2>^ lbs. of ordinary sal soda. 

Soap containing much rosin, and therefore apt to be sticky, 
and to crack when filled with sal soda alone, may also be filled 
with a little starch in addition, which binds the materials to¬ 
gether and absorbs much of the moisture, facilitating framing 
by preventing the separation of the materials. For a soap made 






Settled Soaps. 


201 


of tallow and 75% rosin, for instance, 9 to 10% soda solution, to 
which \ l /z to 2% starch have been added, may be used to advan¬ 
tage. (See chapter on “Filling-,” under “Starch,” page 81). 

Soap made of part cocoanut oil, owing to its ability to absorb 
large quantities of salts without separating, will not become 
cracky so easily as a tallow-rosin soap. 

Instead of sal soda or soda ash solution alone, with perhaps 
a little starch, many other additional filling materials may be 
employed for this kind of soaps, but as said before, they cause a 
more or less unsightly appearance of the soap on drying. 

For instance, silicate of soda at 35° B. may be added 
by crutching, from 2% upwards, as the soap will stand it, and 
according as more or less sal soda is added. 

About 2% silicate and 8% soda solution, to which 8% of talc 
may also have been added, are frequently used; or 8 to 10% sal 
soda and 5% of silicate. 

Still another mixture: 100 lbs. sal soda (or an equivalent 
weight of soda ash), 10 lbs. borax, 10 lbs. pearl ash, dissolved 
together, to 38° to 40° B. Add 10 to 12 lbs. starch, and use from 
6% to 8% or more of this mixture, according as the soap will 
take it. 

Where no silicate or starch are used, silex is sometimes 
crutched in, although this material is certainly not to be recom¬ 
mended in a laundry soap, and it is not so much used now as 
formerly. The silex is first mixed with the warm sal soda before 
adding it to the soap in the crutcher. 

For further particulars on filling see the chapter on these 
materials on pages 79-86. 

Stripping, Cutting, Drying, Etc 

It requires from one to three days for the soap to solidify suf¬ 
ficiently so that it can be “stripped,” that is to say the frame 
taken off, if iron frames are used. In wooden frames about a 
week is necessary. Another day is then allowed for further cool¬ 
ing, and then the soap is cut into slabs and bars by the machinery 
described heretofore. 

The bars are stacked on racks for drying slightly, until a 
somewhat dry pellicle is formed on their surface. 

The drying operation is still largely conducted by simply 
exposing the soap to the action of the atmosphere. This requires 
much room, and the drying proceeds in a hap-hazard wa} 7 , ac- 


Different fill i n g 
mixtures. 


202 


Settled Soaps. 


Natui’e of nigre. 


cording- to the weather, but slowly at best. Some manufacturers 
heat their drying room by steam apparatus, to make the process 
at least positive. 

The most rapid drying is secured by the fan apparatus de¬ 
scribed in chapter V., which also produces a glossy skin on the 
soap that facilitates pressing and improves its appearance. 

The operation of pressing will be described in a separate 
chapter. 


The Nigee. 

The “nigre” is a mixture of soap, water, and various salts 
and impurities which are washed out and precipitated during the 
settling operation; there is also present the excess of alkali that 
was left in the kettle after drawing the strengthening lye, and 
coloring matter incidently introduced with the various raw 
materials. 

The formation of “nigre” in the kettle takes place as follows: 
The strengthening lye, it will be observed, was so strong when 
drawn off that it was unable to hold any soap (or at all events 
but very little) in solution. On diluting the remaining traces 
of this lye, however, as is done in the finishing change, its 
capacity for dissolving soap is proportionately increased, and in 
consequence there is formed a weak lye, holding in solution more 
or less soap and the salts, etc., already enumerated. This solu¬ 
tion, being specifically heavier than pure soap, sinks to the 
bottom of the kettle, taking various impurities along in so doing, 
thereby clarifying the soap and constituting the “nigre.” 

It is evident from the explanation that the more water is 
used in thinning the soap the more soap will be dissolved, and 
the larger will be the nigre in proportion to the pure soap above 
it. At the same time the pure soap also holds more water when 
the nigre is larger. 

Rosin and soft greases form soap which is more soluble in 
water containing salts than is pure tallow soap, and olein soap 
is more soluble than that from stearin, so that the nigre if grain¬ 
ed on salt will furnish a soau which has slightly more rosin and 
soft fatty acids in its composition and is therefore softer than 
the good soap in the kettle, besides being mixed with more col¬ 
oring matter, with insoluble soaps formed by lime, iron, etc., and 
with impurities generally. Still, the proportion of good soap in 
the nigre is very large and must be utilized in some wa y. 



Settled Soaps. 


203 


The nigre will constitute about one quarter of the contents 
of the kettle (more or less, according’ as the soap was settled 
coarsely or finely) and may be utilized in various different ways, 
of which those generally employed may be enumerated as follows: 

I. The nigre resulting’ from a batch of soap from fresh utilizing the 
materials that were boiled in a clean kettle is left in the latter; 

fresh stock is added and lye run in until the stock is saponified ; 
the boil is then finished as usual. The nigre which results from 
settling- this batch is still softer and more impure than the first 
nigre, and is g-enerally used, together with fresh stock (mostly 
of somewhat inferior quality) for a second quality of soap. This 
is repeated throug-h several boils of second grade soap, when the 
nigre is finally used for a still lower quality of brown soap, in 
which common fats and a small proportion of palm oil (the latter 
for improving- the color) may be used. The nigre again result¬ 
ing from settling this dark soap is saved, until from successive 
similiar batches enough of it accumulates to make a very low 
grade of soap from it. 

II. The nigre, after passing through two or three batches 
of the best soap, is separated by adding salt and boiling. A 
frothy soap is thereby separated, from which the salt solution is 
run away after a sufficient rest. The soap so separated is saved 
in a kettle by itself (or in frames), and when enough of it is on 
hand to make a batch it is boiled on weak lye and again grained 
on salt. The waste lye is then settled and run away; the soap 
receives a somewhat coarse finish, is settled and then framed for 
occasional use in some lower grade of soap. The nigre resulting 
from this settling operation is set aside for use in a very dark 
grade. 

III. The following plan will, in many cases, be found use¬ 
ful: The nigre is used first for the lighter colored soaps, then 
for the darker ones, and when it finally becomes advisable to use 
it up, so as to be rid of it, it is grained, the waste lye run away, 
and the soap washed out by boiling with plenty of weak lye, at, 
say, 3-6-" B., so as to remove all the salt. Then it is fitted to 
form a very thin grain, so that the lye is not quite clear, but con¬ 
tains just a trace of nigre, and time is allowed for settling. The 
soap so obtained contains an excess of alkaline strength, which 
is taken out by adding, in the crutcher, an equivalent proportion 
of cocoanut oil. The soap is filled with sal soda, just as in the 
case of ordinary settled soap, and then framed. 


204 


Settled Soaps. 


Usingscraps with¬ 
out remelting. 


IV. In some factories the nigre is “bleached,” and the 
kettle then charged with fresh stock on top of it, using - each nigre in 
this manner without making - dark soap. The bleaching maybe 
carried out as follows: The nigre is grained on salt and the 
waste lye run off. Water is then run in to close the soap, and 
enough lye to give a little sharpness. Tin crystals (stannous 
chloride, muriate of tin) are then added, previously dissolved in 
a little water, about 1)4 to 2 lbs. of this bleaching agent being 
used for every 300 lbs. of nigre, according to how much rosin it 
contains. Open steam is turned on and the mass boiled for 2 or 
2)4 hours. When the soap is again grained on salt and the waste 
lye run off, the nigre will be found as light colored as the soap 
was from which it was obtained. It is then used as stated above, 
by being boiled together with fresh stock. Another way of 
bleaching nigres is by the use of hypochlorite of soda, a process 
already described under the heading of Cottonseed Foots, in 
chapter II. 

As the nigre deteriorates more and more, with each succeed¬ 
ing batch, irrespective of its color, it may be well to use it up 
from time to time anyway, to get rid of it. 

V. Other uses have been occasionally recommended, such 
as making “soap stock,” for laundries, soap powder, floating 
soap (taking advantage of the frothy nature of the soap result¬ 
ing from graining nigre), etc., etc. Considering, however, the 
inferior nature of the nigre, the values of the different sugges¬ 
tions may be readily estimated b} T the soap maker. It is useless 
to describe the proceeding in such cases, since they are rarely 
employed, and are not difficult to imagine. 

Scraps of Soap. 

The “scraps” or trimmings of soap resulting from cutting 
up a frame into slabs and bars are best utilized byremelting them 
in a special apparatus, as hereafter described. (Chapter XIV.) 
But where such an apparatus is not used in the factory, other 
expedients must be employed. One way to use them, if they had 
been filled with sal soda, is to add them in the kettle at the end 
of the rosin change, in a succeeding boil, so that the carbonate 
of soda may be utilized by combining it with the rosin. (If 
added in the kettle when saponifying neutral fats, the filling 
would go into the waste lye and be lost.) 

A more satisfactory method, which also saves the kettle 




Settled Soaps. 


205 


space, consists in adding- the scraps, cut into small pieces, to the 
soap in the crutcher, the latter being- used somewhat warmer 
than usual in order to make up for the low temperature of the 
scraps, and the filling- used somewhat weaker, to make up for 
the dry condition of the chips. This has at least one advantage, 
namely—that the heat used for remelting is saved, but it makes 
the correct framing of the new soap somewhat more difficult. 
(See, also, the chapter on “Remelting” and under “Cold 
Soap.”) 


WHITE SETTLED SOAP. 

To make a white settled soap the properties of the rosin 
used in the yellow soap just described are generally supplied in 
some other way, namely, by a proper selection of fats, as a set¬ 
tled soap from tallow or similar fats alone dries out strongly, 
and thereby becomes very hard and too difficultly soluble for 
practical use. Advantage is in this case most frequently taken 
of the property of cocoanut oil soap to retain moisture, thereby 
not only preventing undue drying, but also—to a great extent 
at least—the general discoloration to which a pure tallow soap 
is subject on aging. The addition of cocoanut oil also aids the 
settling out of impurities, as may be seen from the fact that the 
nigre from a pure tallow soap is much lighter in color than that 
from a soap in which some cocoanut oil was used with the tal¬ 
low. 

Tallow and 10 per cent of cocoanut oil furnish a good, hard, 
and white soap, suitable for all household purposes, and the fol¬ 
lowing description of making a white settled soap is based on 
this composition. 

Other fats may of course also be used, instead of the tallow, 
such as lard, and bleached palm oil, for instance. Grease gene¬ 
rally furnishes off-colored products, and cotton seed oil causes 
yellow spots on drying, especially if the soap is not filled. 

First Change. 

The tallow and cocoanut oil are clarified together in the 
same manner as stated under “ Rosin Soap,” and are then saponi¬ 
fied, beginning with lye at say 12° B., of which about one 
pound is run into the kettle for every three pounds of stock, 
while boiling on open steam. 

When the quantity of lye stated has been well boiled with 


i 


Stock for white 
settled soap. 


206 


Settled Soaps. 


the fats, the contents of the kettle form a homogeneous mixture, 
whereupon saponification is continued by running in strong lye 
at 25 to 30° B. which is run in slowly, under gentle boiling, so 
that the boiling is not interrupted, nor the soap allowed to 
open. If the latter irregularity should take place, it is a sign 
that the lye has been added too fast, and a little more water 
may then have to be added until the mass closes again. 

When the soap becomes transparent and tastes sharp, the 
saponification change is finished. In order to make sure on this 
point, a few minutes’ rest is allowed, and if the sharp taste re¬ 
mains on then boiling again, enough lye has been added. Other¬ 
wise a little more lye must be run in and again boiled 
through. 

During this change the lye must never be allowed to run in 
so slowly that the strength is at any time entirely absorbed, nor 
so fast that the soap opens. 

If the lye is used too strong or in great excess, the soap 
opens and saponification is retarded by it; on the other hand, if 
the soap is weak it will suddenly become thick and difficult to 
manage. In the latter case strong lye must be run in at once, 
and the soap be thoroughly crutched, while the steam is only 
turned on far enough to barely keep up boiling. 

When the paste is transparent and retains a slight sharp¬ 
ness after the lye has been turned off for some minutes, it is 
grained with salt or brine, and the waste lye allowed to settle, 
as described in the previous boil; or the kettle may be opened 
with lye, this removing coloring matters more effectively and at 
the same time being at times preferred in regard to the recovery 
of glycerin from the waste lye. 

When cocoanut oil is saponified it naturally has a somewhat 
sharp taste which is sometimes mistaken—by those not used to 
working with it—for alkaline strength. 

The first change may also be carried out by first saponi¬ 
fying the tallow alone, and graining it on salt as in the rosin 
soap described; then running off the waste lye and adding the 
cocoanut oil, and boiling with more lye in much the same man¬ 
ner as the rosin was saponified in the same boil just referred to. 
The weaker lye employed in this case for the tallow is supposed 
by some to bring about a larger yield of soap, as it is more 
favorable to thorough saponification. 


Settled Soaps. 


207 


Strengthening Change. 

After drawing- the waste lye from the first change, new lye 
at from 20-24° B. is run into the kettle and the soap boiled for an 
hour or longer, until all parts of the fat are thoroughly saponi¬ 
fied. 

The strength and quantity of the lye required for the 
strengthening change depends on circumstances. If the soap 
was not grained strongly at the end of the first change, it will 
hold considerable water, and a stronger lye is then used than 
would be proper if the soap contained but little water. Again, 
if open steam only is used, the lye may be stronger than when 
a closed coil is used for boiling, on account of the water intro¬ 
duced by the condensing steam. As to the quantity, about 30 
gallons of lye to 1,000 lbs. of fat used will be required for an 
averaged sized kettle. 

i 

At the end of this change the soap should be in a soft, large 
curd, so as to drop the lye well; if grained too far, it will require 
too much water in thinning and cause an excessive nigre. 

The lye from the strengthening change is carefully removed 
after a sufficient rest, so as to free the soap from it as perfectly 
as possible, and is saved to be used for its strength for some dark 
soap. 

Finishing. 

Water is run into the soap to thin it, open steam being 
turned on for gently boiling the mass. The quantity of water 
again depends on the condition of the soap, and may be 8 to 10 
gallons for every 1,000 lbs. of stock to begin with. The soap 
becomes close, and a sample must be smooth on the top. If it 
rises high in the kettle and the sample separates no lye, it is 
sufficiently thinned out; otherwise more water must be added 
and well boiled through. The soap is then allowed to settle un¬ 
til cooled off to about 160° F. and the good soap framed. 

Framing. 

The soap is generally framed pure, as it is sufficiently hard 
without filling (and in that case, if made from good stock, would 
answer well for “milling” into toilet soaps). The larger the 
frames used, the slower will the soap cool, whereby the texture 
will improve and the soap be harder on cutting than if cooled 
rapidly in small frames. But if wanted , this soap may be filled 


208 


Settled Soaps. 


Castile soap. 


Settled soap with¬ 
out cocoanut oil 
or rosin. 


—like a rosin soap—in the crutcher, with about 8 per cent soda 
solution (36° B.), to which may be added from 6 to 8 lbs. of 
borax, or other filling- desired, to each frame of 1,100 lbs. 

General Remarks. 

As the manufacture of this soap resembles in most particu¬ 
lars that of the rosin soap already described, it was unnecessary 
to repeat here all the details reg-arding- the various operations; 
for further particulars the reader is therefore referred back to 
the description of making “Rosin Soap” (page 185, etc.) 

It may be remarked in this connection that the true white 
Castile soap (so-called from the former kingdom of Spain, where 
this soap was originally made in very large quantities), is made 
by “settling” a pure olive oil soap. In this country it is imi¬ 
tated by making a similar article, in which the olive oil is sub¬ 
stituted by such fats (in various proportions) as tallow, cotton 
seed oil, cotton stearine, bleached palm oil, cocoanut oil, etc. 
The true Castile soap, as may be readily imagined, becomes 
extremely hard with age, and forms a slimy mixture with cold 
water rather than a lather. It is used mostly for pharmaceuti¬ 
cal and technical purposes (by silk dyers, etc.); and according 
to the use for which the American products are intended, its 
properties are more or less sought to be imitated. There are 
also numerous soaps brought on the market which simply trade 
on the good name of the original, and are made after almost 
all processes of soap making known to the trade, having gen¬ 
erally no similarity whatever to the true Castile soap. 

An imitation of Castile soap for manufacturing purposes is 
often made in this country from equal parts of tallow and cotton 
seed oil, settled coarsely and crutched till nearly cold, without 
filling. It is sold in barrels, or framed and cut like other 
soaps. 

A settled soap from tallow alone, or from cotton seed oil 
alone, or from a mixture of the two, may be made in the same 
manner as other settled soaps, but it should be thinned down 
only so far as to be still in a half-grained state. If it were 
thinned out as much as is usual in a rosin soap it would form an 
excessively large nigre, owing to the great quantity of water re¬ 
quired for thinning such a soap to that degree. The good soap 
would also hold considerable water and shrink very much on 
drying. Such soaps ma}^ also be filled like a settled rosin soap, 


Settled Soaps. 


209 


but will not take quite as much filling. If made of cotton seed 
oil only the soap will be rather too soft for cutting - it into bars. 

A somewhat similar soap as the one here described is fre- A modified pro 
quently made in Germany by a process not well known here, 
and which may be briefly described, as follows: 

The tallow is saponified alone, grained on salt and boiled 
well on fresh lye of 15° B. (over open fire in most cases) till the 
soap is well grained; 25% of cocoanut oil is then added and 
boiled until the sharpness of the strengthening - lye is absorbed, 
about \]/2 lbs. lye at the strength named being used for each 
pound of cocoanut oil. The thickly fluid soap formed by his 
operation is then thinned with salt water until a samp e 
slightly wet on cooling. The kettle is then covered, the soap 
allowed to settle and framed at about 190 : F. (The formation 
of nigre in this case is caused by the decreased capacity of the 
water to hold the soap in solution, when salt water is added; 
this action depends on the property of cocoanut oil soap of dis¬ 
solving in moderately strong salt water, and not enough salt 
water is added to entirely separate the soap.) 

When, in making a rosin soap by this same process much 
or dark rosin is used, they sometimes add the latter to the nigre 
of the last boil, run in a rather weak lye to saponify the rosin, 
and add enough salt so that the waste lye still contains some 
'nigre; after settling thereafter much of the coloring matter of 
the rosin is got rid of before fresh fat enters the kettle. 

In this connection may be mentioned also the plan, some¬ 
times adopted, of saponifying the rosin separately by means of 
carbonate of soda (which is cheaper and assists in discharging 
color, then separating by the use of salt, and adding this pro¬ 
duct so obtained to the soap in the kettle). 




' 
































. 






















































CHAPTER VIII. 


Boiled Down Soaps. 


It has already been stated (page 180) that the “ boiling 
down” of soap is a process by which, in the first place, a pro¬ 
duct is made which contains less water in its composition than 
is commonly met with in ordinary soaps. As a consequence the 
effect of this operation of “ boiling down” is to render the soap 
harder, less rapidly soluble, and—unless the boiling down is 
carried very far—to produce the natural “mottle” or “marble,” 
which in former times served as a guarantee that the soap con¬ 
tained no excessive amount of water. The marbled appearance 
of soap that has been boiled down is caused, according to the 
generally accepted theory, by a process of crystallization through 
which the coloring matters in the soap are expelled from the 
white, crystalline parts (stearine soap), and become enclosed in 
the more slowly solidifying, non-crystalline portions (olein soap), 
coloring the latter by their presence. On closely examining 
such a soap under a microscope, it seems that the small particles 
of stearine soap become so closely packed together that they 
force the particles of coloring matter into the softer, more 
spongy olein soap. (It may be doubted if the term “crystal¬ 
lization” can be rightfully used for this phenomenon, considering 
that the mottle forms at so high a temperature, at which a real 
formation of crystals can hardly take place). In the old process 
of making the true Castile soap, if too much water is present, 
the thin consistency of the soap causes the coloring matters to 
settle to the bottom of the frame, and from this circumstance 
arose the (formerly quite correct) belief that a marbled soap was 
one necessarily containing but little water. This was un- 


Tlie mottle 




Boiled Down Soaps. 


Stock for German 
mottled soap. 




91 9 

doubtedly true in the olden times, but at present there are ways 
of making- marbled soaps that contain more water than was ever 
dreamed of in those times, even in reg-ard to their white soaps. 

Of the boiled down soaps there is really but one variety that 
is made in this country to-day to any considerable extent—one 
that is g-enerally known as “German Mottled.” The genuine 
Marbled Castile is also made by boiling- down a soap (made by 
saponifying- olive oil), but the soaps made in imitation of it in 
this country are mostly made in almost every way but by boil¬ 
ing- down. 

GERMAN MOTTLED SOAP. 

This really excellent soap, as orig-inally made in Germany 
by the oldest process known, was composed of tallow and lye 
made from wood ashes; now it is made there in various qualities 
from a variety of fats and oils, and artificial soda. The fat used 
principally for German mottled soap in the United States isoleic 
acid (red oil), which is eminently suitable for this article. 

Briefly stated, “ German Mottled ” is a soap which has 
(g-enerally) been settled, and is then boiled on “ pickle ” to de¬ 
prive it of water. The fat is therefore selected, and the manu- 
ture in the first stag-es carried out in a manner similar as in the 
case of the settled soaps described in the foreg-oing- pag-es, with 
this exception, that the composition of fats used in “German 
Mottled ” should be somewhat softer on an average than is used 
for simple settled soap, as otherwise the finished product is very 
apt to become exceedingly hard and brittle on drying, and to 
crack. These soaps are therefore best made of red oil, or cot¬ 
ton seed oil, or of tallow and soft grease or any similar combi¬ 
nation of stock, and, general^, without the use of rosin. 

On account of the softness and great solubility of red oil 
soap a smaller proportion of rosin used in connection with it, if 
any, is here preferable to that used in a settled tallow-rosin 
soap. Besides, a red oil soap darkens considerably on aging, and 
much, or very dark rosin, is for this reason also undesirable. 
With cotton seed oil, however, from 25 to 30 per cent of rosin 
gives a good product. 

Having already described in the previous chapter the saponi¬ 
fication of tallow, we shall base the following description of 
making “German Mottled” soap principally on the use of red 
oil, as this gives us an opportunity of noting the difference be¬ 
tween working tallow and working with red oil. 




Boiled Down Soaps. 


213 


First Change. 

The lye required for saponifying- the red oil is run into the 
kettle and broug-ht to a boil. 

This lye may be caustic lye, or (red oil being a free fatty 
acid), it may be prepared by dissolving carbonate of soda (soda 
ash) in water by the aid of steam, until it marks 21 B. when 
hot. This is allowed to settle for a da} 7 or two, and the clear 
solution run off into the kettle. Supposing a pure grade of soda 
ash to have been used, about equal weights of lye and red oil 
will then be required for saponification. Of ati impure alkali 
more would, of course, have to be used, as the inert salt does not 
take part in the saponification. [In case carbonate of soda is 
used, carbonic acid is evolved during boiling, which is danger¬ 
ous to inhale in considerable quantities. As it is heavier than 
air, some provision must be made to carry it off therefore; on ac¬ 
count of its weight it will not rise like steam, but, although in¬ 
visible, remains near the floor, so that it is best got rid of by 
opening the doors of the kettle room to let it escape into the 
atmosphere.] 

In the boiling lye 25 to 30 lbs. of salt (according to purity 
of lye) may be dissolved for every 1,000 lbs. of red oil, as an 
additional safeguard against “ bunching.” The lye being at a 
brisk boil, the red oil is run in and good boiling kept up. If 
boiling is allowed to become slow, lumps are liable to form which 
are difficult to dissolve again; and as the fatty acid combines 
very readily with the alkali, the operation of saponifying pro¬ 
ceeds most rapidly and easily if the red oil is run into the kettle 
already somewhat heated. For the same reason it is advisable 
to run the oil into the kettle over a piece of sheet iron, so ar¬ 
ranged that it breaks up the mass in a spray-like manner, in¬ 
stead of running it in in a thick, solid stream. 

After all the fatty acid has been run into the lye, boiling is 
. continued for an hour or more, until all is thoroughly saponified, 
and the soap has become separated from the waste lye. 

If cotton seed oil, soft grease, etc., are used instead of red oil, 
the first change is of course conducted in the ordinary manner, 
as has been described under “Settled Soap.” The reversal of 
the process (/. ^., running the fatty matter into the lye, instead 
of vice versa , when red oil is used) is generally adopted because 
the ordinary mode of conducting the saponification of neutral 


Method of saponi' 
lying red oil. 


Precautions when 
soda ash is used*- 


Means of prevent' 
ing bunching. 


214 


Boiled Down Soaps. 


fats would result in an aggravated case of “ bunching ” when 
fatty acids are saponified. 

******** 

[The waste lye may be run away after sufficient rest to settle 
the same, and in case any rosin is to be used in the soap, it may 
then be added for saponification, just as in making an ordinary 
settled rosin soap. As said before, “ German Mottled ” is ordi¬ 
narily made without rosin, but there are some manufacturers, 
especially those who use other stock than red oil, whose German 
Mottled soap contains about 25% of rosin to each 100 lbs. of fat. 
The saponification of rosin having already been described, we 
will here give another mode of working which maybe adopted— 
to suit the opinion of the soap-maker—according to the purity 
and color of the stock used. This method is as follows : 

Run into the kettle (without having run off the waste lye) 
about 520 lbs. of caustic lye at say 35 B. for every 1,000 lbs. of 
rosin to be used. Then add the broken rosin. 

The exact strength of lye most practicable to be used in this 
case cannot be given, as this depends on whether open or closed 
steam, or both, are used for boiling and on the quality of the 
rosin, and particularly on the amount of waste lye in the kettle. 
If only closed steam is used the quantity of lye named may have 
to be diluted with water. The lye is here used very strong on 
account of the large quantity of water contained in the kettle 
when the waste lye has not been previously run off. 

When all the rosin has been added the soap should no longer 
be open, but rather in the condition of a soap thinned out in 
“settling,” as it will then be more readily saponified. After 
boiling well when the rosin has been added, the soap is grained 
with salt and the waste lye drawn off after sufficient rest. 

The soap now is practically in the same condition as it was 
in the boil of settled soap after the rosin change, only it is softer 
on account of the softer stock used. It may now be repeatedly 
drawn together with water, or better with weak lye, and grained 
with salt to wash out the impurities as much as desired.] 
******** 

When the stock is thoroughly saponified the soap is grained 
with salt, and one or two additional changes are given to im- 
improve the color and consistency, after which it is boiled down, 
as described below, or instead it may be first settled. 


Boiled Down Soaps. 


215 


Settling. 


The thoroughly formed soap may now be “boiled down” 
at once, but for a first-class article, for improving the color, or 
wnen dark stock has been used, the soap is first thinned with 
water and allowed to drop the nigre, whereby it is clarified, and 
the free alkali removed, which is quite as important in this as 
in “settled” soap. This process has been described before, 
and need not, therefore, be repeated here; it may be remarked, 
however, that the finer the soap is settled the larger will not 
only be the nigre, but also the proportion of water in the clear 
soap, and the longer time will then of course be required for the 
soiling down. A short settle only is, therefore, usually made 
for German mottled soap. 


Settling- not abso 
lutel y necessary 


Boiling Down. 

The clear soap, if it had ueen settled, is pumped off from 
the nigre through a strainer into a clean kettle, into which the 
“ pickle ” has previously been run (or if the soap was not settled 
the pickle is simply run into the kettle), and closed steam is turn¬ 
ed on. In regard to the proper composition and strength of this 
pickle much diversity of opinion exists. 

As to ttie composition : The pickle may consist simply of salt 
dissolved in water. Boiled down on this the soap will lose part 
of the water it holds, will mottle very nicely, and will form a sat¬ 
isfactory product; only it will have, on solidifying, a dry, brittle 
texture, which is not at all desirable. To obviate this drawback 
carbonate of soda (soda ash) is frequently added to the salt water 
to form the pickle. The texture of a soap boiled down on a pickle 
consisting of half salt and half soda ash solution is perceptibly 
better than if boiled on a salt solution alone, but here the trouble 
is that the traces of carbonate remaining in the soap will cause 
the latter to effloresce on drying. According to the composition 
of the pickle the texture may, therefore,be improved, at the ex¬ 
pense of appearance. 

As to strength : When boiling the soap on pickle the latter 
tends to become more concentrated by the evaporation of water, 
but at the same time it withdraws water again from the soap. 
In this manner it is possible to boil on pickle until the soap has 
lost considerable water, and yet the pickle itself will be of the 
same strength as at the commencement of the operation. It is 
obvious, however, that the proper strength at which the pickle 


\ 


216 


Boiled Down Soaps. 


Saving boil 
down. 


is first introducer! depends greatly on various circumstances. A 
soap may have been more or less finely settled and consequently 
contains more or less water to be evaporated. 

The same is true in regard to the kind of stock (and propor¬ 
tion of rosin, if any, used). Again, the arrangement of the steam 
coil and shape of kettle may be such as to require a greater or 
smaller quantity of pickle; if a large quantity is used it should 
not be so weak, in ord":r not to introduce too much water with it. 
A finely settled soap therefore requires stronger pickle for boil¬ 
ing down in a reasonable length of time than a soap which con¬ 
tains but very little water to be evaporated. Besides, soap 
makers who have had long experience in making this soap do not 
agree in this respect in their opinions, even under the same con¬ 
ditions regarding stock, etc. The proper strength of pickle for 
this purpose is variously named at from 8° to 20 B. (and by some 
even up to dry salt). The stronger the pickle the more rapidly 
will the operation be finished. 

The soap and the pickle made b} T dissolving salt alone, or 

salt and soda ash, in water, to a strength of from say 14 to 18 3 

* 

B., are boiled together on closed steam, and the progress of the 
operation is closely watched. The appearance of the soap and 
the strength of the pickle is carefully observed from time to time, 
as tlm boiling proceeds, and after making a few boils of a given 
composition as to fat and rosin the soap boiler will have gained 
the necessary experience and correct judgment in the matter, 
which can only be acquired by practice and intelligent study. 

The mottle—formed by impurities of the raw materials in¬ 
closed in the non-crystalline portions of the soap—can only 
form when the hot soap has a certain degree of fluidity. It will 
develop strongly if the soap contains much water; in other words, 
if the mottle is too pronounced the soap has not been boiled 
down far enough. If boiled too far, on the other hand, the mot¬ 
tle cannot form at all, as the lack of water then renders the soap 
too thick to allow of proper crystallization in the hot soap by 
means of which the mottle is to be formed. The salt used in 
boiling down supplies the necessary mobility of the mass to 
permit crystallization. 

A method, not exactly to be recommended, but sometimes 
adopted in order to save boiling down so far, is to boil down as 
much as desired and sifting some finely ground, pure soda ash 
into the soap (in the crutcher). The soda ash absorbs the sur- 


Boiled Down Soaps. 


217 


plus of moisture and acts as filling*. No special proportion of 
soda ash is necessary to be observed, as it is not likely to effloresce 
(as it would certainly do in the case of settled soap, unless used 
just in the right proportion). 

F NAMING. 

When boiling* has proceeded to a point judged to give the 
proper mottle, a rest of several hours is allowed to separate the 
pickle, and the soap is then ready for framing, which is carried 
out in the same manner as in the case of settled soap. In small 
iron frames the soap cools quickly and shows but little mottle; if 
a more pronounced mottle is desired, large wooden frames are 
used. 

Filling might also be added, if desired, but generally boiled 
down soap is framed pure, as there is no real benefit regarding 
the quality of soap in boiling down if filling is to be added. If 
the stock used in this soap was not thoroughly saponified it will 
have a tendency to retain an admixture of some of the pickle, 
and thereby cause trouble in the frame. 

Pressing. 

On account of the “short” texture of the soap it is not press¬ 
ed in the ordinary manner, but merely cut in bars and stamped 
on the sides with a simple stamp. Potash lye used for part of 
the soda lye, especially if soda ash was used in the pickle, has 
the property of improving their texture so much that the soap 
so made can be pressed in the ordinary manner. 

General Remarks. 

In order to avoid unnecessary repetition, only the considera¬ 
tions peculiar to boiled down soaps have been mentioned in detail 
in this chapter;' for further particulars refer to the chapter on 
settled soaps. Some additional practical points are contained in 
the following somewhat different description of the making of 
German Mottled, as carried out in some factories: 

Nigre left over from settled soap can be used to start the 
boiling; it should be grained out with salt and the spent ly r e re¬ 
moved;* then run into the kettle about 1,000 lbs. of 8 to 10° salt 
water for each 20,000 lbs. of soap to be made. Bring the salt 
water and nigre to a boil, then run in the stock and lye at 30 to 
40 slowly, so that the soap is kept just open enough that it would 


218 


Boiled Down Soaps. 


not drop a nigre if allowed to settle. Should the soap at any 
time be too open so that the stock will not combine with the lye, 
one may either run in water, or put in some of the rosin intend¬ 
ed to be used anyway, or simply let the kettle rest for a time till 
the soap takes up the lye again. When all the stock has 
been run into the kettle and saponified, the soap should run off 
the paddle in large, soft flakes, separate from the lye which 
should hardly have any strength in it. To prevent the soap from 
closing up entirely it may be necessary to add salt toward the 
end of the boiling. If rosin is used it is generally put in after 
the grease or tallow is saponified. After running off the spent 
lye, water is added—enough that the soap will drop a small 
nigre,—or salt water and some lye is used and boiling continued 
for 2 to 3 hours in a slightly open state; care must be taken not 
to get foamy soap by running the water in too fast, as this 
would delay the finishing of the soap later on. If ilie method of 
taking out a small nigre is adopted, the latter is run out of the 
kettleand the remaining soap boiled with salt water of 14-16°; then 
turn off steam and let it rest in cold weather for 4 to 5 hours, or 
in summer over night. When the soap has cooled to ISO'' F., 
pump it to the crutcher and add from 10 to 15 lbs. of soda 
ash (sifted in to prevent lumps). This method does not produce 
a good mottle and the soap is somewhat liable to whitewash. 
Silicate, mineral soap stock, and even silex has been crutched 
into such soap. Instead of taking out a nigre, as mentioned, the 
soap may be given 2 or 3 washings with salt water and finally 
finished by adding enough salt that the spent lye indicates 10- 
14 B. The spent lye must be stronger in proportion as the 
amount of oil or rosin in the stock is larger. The hotter the soap 
is framed, the larger will be the mottle; the frames should be 
covered to prevent the surface from cooling too quickly. Wood¬ 
en frames of 1500 to 2000 lbs. favor the mottling. As German 
Mottled soap is too heavy to pump out of the kettle, it is con¬ 
venient to have a 4 or 5-inch cock valve at the side of the kettle, 
above the line of spent lye, as the soap will not run through a 
swing pipe. In small factories that have no remelter, the scraps 
from settled rosin soap can be used in place of rosin in German 
Mottled and any sal soda that goes into the spent lye can be re¬ 
covered in the next batch by boiling with red oil or rosin. If 
cottonseed foots are used, these have to be saponified separately 
and washed repeatedly or settled before the rest of the stock is 


Boiled Down Soaps. 


219 


mixed with them; it is also possible to make a pretty fair article 
from cottonseed foots alone and 10 to 20% of rosin, but as such 
soaps dissolve very easily, they can be greatly improved by the 
addition of 20% of tallow. 

* * * * * * * 

In this place it may be proper to briefly state how the gen¬ 
uine Marbled Castile soap, also known as “Marseilles” soap, 
is made in European countries. 

Olive oil (from the second pressure of the fruit), with or 
without the addition of other oils, is saponified with lye at from Gemune 

, r J soap, 

10 to 20° B. Coloring mattei is then added, such as copperas 
(sulphate of iron), which, together with the sulphur compounds 
either present in the crude soda or otherwise added afterwards, 
causes a greenish black color by the formation of ferrous sul¬ 
phide. The marble formed by these materials changes to yellow 
on exposure to the atmosphere. The soap is grained on strong 
lye, which contains considerable salt in solution, and the waste 
lye is then run off. It is then once more boiled on strong 
“salted” lye and the waste lye drawn off again. Fresh lye of 
22 to 25° B. is then added and the soap boiled until saturated 
with alkali and strongly boiled down. A little water is then 
carefully added to bring the soap to the right condition for 
marbling, or successive portions of lye, gradually decreasing in 
strength, are used for the same purpose. The soap is then run 
into large wooden frames and left to crystallize, in order to form 
the marble. (The coloring matters collect in the non crystalline 
portions.) 

For white castile soap the process is the same, but omitting 
the coloring, and thinning the soap for “settling,” first with lye 
at 6 to 7° and then with still weaker lye, and at last with water. 

Of course there are variations from this process, as well as 
in making all other soaps. The appliances and lye used in the 
foreign countries are very different from those used in the United 
States. The lye is still made to some extent from kelp, or more 
frequently by causticizing soda ash. Differently prepared lyes 
are used for different operations, and the boiling of a batch of 
soap over the open fire still used there, and the many changes of 
lye, generally take from three to four days. 

Imitations, resembling the genuine article more or less, are 
mostly made of cottonseed oil and some tallow. 

It will be noticed that the mottle is produced from the same 


f 


Castile 


220 


Boiled Down Soaps. 


\ 


cause in true Castile soap as in “ German Mottled,” onl} r the con¬ 
ditions required for mottling are brought about in different ways, 
for while in the former the soap is boiled to a grain and then 
thinned with lye or water, German Mottled is made by boiling 
on pickle a soap already containing too much water. In order 
to make the mottle more intense, coloring matter may be added 
to the soap. 

Soaps that have been boiled down immediately after saponifi¬ 
cation, without settling, invariabl} 7 contain some free alkali. For 
this reason sulphate of iron, which was formerly employed as 
coloring matter in such soap, was added in such a manner as to 
combine with the free soda, thereby setting the iron free to form 
the marble and also neutralizing the free soda present. The ox¬ 
ide of iron and other similar pigments now generally used do not 
possess this neutralizing action. 

WHITE BOILED DOWN SOAP. 

If a hard white soap is to be made from soft materials, such as 
cotton seed oil as the only stock, it requires boiling down in order 
to overcome the natural softness of a pure cotton seed oil soap. 
Such soaps are made but little at the present time, owing to the 
relative prices of fats, oils and rosin. Their manufacture may be 
briefly described as follows : 

(As was said in the description of cotton seed oil,this stock, 
when used in boiled-down soaps, has not that tendency of caus¬ 
ing yellow spots, as in settled soaps.) 

First Change. 

The oil is run into the kettle, along with twenty gallons of 
water for each 1,000 lbs. of stock. Open steam is turned on and 
lye at 15' B. run in. When saponification is approaching its 
completion, the strength of l ve is increased to 20 B. The lye 
should be made of high-grade caustic and plenty of time allowed 
for saponification, as cotton seed oil combines less readily with 
alkalies than other oils and fats. When the soap is well formed 
and has a sharp taste, it is grained with salt in the usual manner, 
so that the clear lye separates from a sample on the paddle. 

Strengthening. 

The spent lye is run off and open steam turned on. Water 
is run in during good boiling till the soap is smooth and bright 


Boiled Down Soaps. 


2">1 

and has the appearance of a soap ready for settling-. Fresh lye 
is then run in and boiling- continued until the soap beg-ins to 
open ag-ain. 

The streng-th of this lye depends somewhat on the amount of 
water previously added for thinning-, on the steam—whether 
closed steam is used tog-ether with open steam or not—and also 
on the judgment of the soap boiler. A strong- lye would finish 
the operation more rapidly, but weaker lye would permit of long- 
er boiling- before the soap becomes grained, and long- boiling-, as 
already stated, is required for thorough saponification, especially 
for cotton seed oil. 

When the soap beg-ins to open, salt is added to assist in 
graining-, so far that the clear lye separates. 

Boiling Down. 

The lye is run off ag-ain and saved for its streng-th. Pickle 
(made in the manner explained under “German Mottled” soap) 
is then gradually run in under constant boiling. When the soap 
has been boiled down like the German Mottled described, steam 
is turned off and the pickle allowed to settle. 

Framing. 

Frame in the manner as in the case of the “German Mot¬ 
tled ” soap. 






























































CHAPTER IX. 


Eschweger Soap. 


While in this country the “settled” soaps are by far the 
most prominent, and the “ boiled-down” soaps constitute nearly 
all the remainder of those made by boiling - , yet there are pro¬ 
cesses of soap-boiling - in which neither of these operations are 

employed. Of this class, for instance, are the “run” soaps 

* 

already referred to, which were made largely, especially in for¬ 
mer years. Another variety also coming under this head is a 
soap sometimes made here in imitation of Castile soap and known 
in Germany as “ Eschweger,” which was first made in 1846 by 
a firm of German soap-makers (Dircks & Thorey). The quan¬ 
tities of these and similar soaps made in this country at the 
present time are not so large as to require on that account an 
extended description of their manufacture in these pages; but, 
inasmuch as it affords an opportunity to show the manner of 
working under different conditions, they may be included to 
some advantage. 

In making most of the better grades of these soaps advan¬ 
tage is taken of the property of a mixture of tallow and cocoanut 
oil to saponify readily with strong lye, thereby furnishing a 
soap containing a comparatively small amount of water, without 
the necessity of separating the waste lye. At the same time the 
foreign salts introduced with the lye—which are run away with 
the wast lye in the ordinary manner of boiling, but remain in 
the soap in the present case—do not exert their usual disturbing 
influence when cocoanut oil is largely used together with the 
tallow or other similar fats. (In fact, a pure cocoanut oil soap 
requires an excessive quantity of salt in order to separate it from 




224 


Eschweger Soap. 


the waste lye, but will appear hard on drying- even if an amount 
of salt solutions is present which would entirely separate a soap 
made of ordinary fats alone). 

In consequence of this latter property, some very high adult¬ 
erated soaps are made by saponifying fats composed largely or 
wholty of cocoanut oil and adding to the soap considerable 
quantities of various salts dissolved in water, 
stock for Each- “Eschweger” is a marbled soap, made by saponifying tal¬ 
low and soft fats, together with about one-third of their weight, 
or more, of cocoanut oil. Owing to the properties of the latter 
oil, such soap, in absorbing considerable salt solutions, thereby 
becomes of a peculiar consistency, while hot, which causes 
crystallization, and thereby the formation of “marble” or 
“ mottle,” on cooling in the frame; at the same time, it holds 
much more water than one that has been mottled by boiling 
down a soap made entirely of soft fats. 

The fat used may be equal parts of tallow and grease, be¬ 
sides cocoanut oil, to one-third of their combined weight, or the 
grease may be substituted by cotton stearin, or cotton seed oil, 
or any similar combination may be used. 

I ndireet method. The tallow and grease may be saponified alone at first, 

grained, the waste lye run away, and the soap so obtained then 
boiled together with the cocoanut oil and the lye required for 
the latter and the required salts; but generally the following 
plan is adopted : 

The fats are clarified together by boiling on open steam, 

■ >.ieci method. an( j the water formed and the impurities drawn off after settling. 

They are then saponified by slow boiling with lye of an average 
strength of say 25 : B., and the quantity of lye is gauged so as 
to have the soap very nearly neutral at the end of the operation, 
as there is no separation whatever of waste lye. All that goes 
into the kettle also goes into the soap (excepting, of course, a 
certain amount of water removed by evaporation). 

The lye should be used as strong as circumstances will per¬ 
mit, since any surplus water can only be removed through eva¬ 
poration by boiling, which is very difficult unless open fire is 
used for making these soaps. For this reason the tallow is in 
some factories saponified alone at first, with weak lye, to insure 
perfect saponification, che waste lye then drawn off, and the 
cocoanut oil added and saponified with stronger lye. 

This soap, when well formed in the kettle, must contain 


Eschweger Soap. 


225 


considerable carbonate (or silicate) of soda and common salt, Saits required for 
so that it may become sufficiently “short” to permit the forma¬ 
tion of a mottle. These salts are added either when saponifica¬ 
tion is nearly complete, as described below, or the presence of 
the carbonate may be insured by using 1 low-grade caustic for 
making the lye, and the salt be added afterwards. During sa¬ 
ponification sufficient lye ahead should always be in the kettle 
(until near the end of the operation) to insure against undue 
thickening of the soap, which is especially liable to occur if tal¬ 
low only is used together with the cocoanut oil. When weaker 
stock, such as cotton seed oil is used, there is less danger of this 
occurring. 

Towards the end of the saponification the physical character 
of the soap must be carefully watched, and the necessary appear¬ 
ance brought about by various additions, according to circum¬ 
stances, as follows : 

If the soap formed is thin, and a sample set on glass has a signs of properly 
gray ring around it, has a dull appearance and sharp taste, it 
indicates an excess of lye, and in this case enough cocoanut oil 
must be added to take out this surplus strength. 

If the sample is thick, glassy, and tough while hot, and soft 
on cooling, and appears heavy, the steam escaping by forcibly 
“puffing” through the mass, more lye is required. If it is soft 
on cooling and yet sharp, more water must be added, as the lye 
has then been too strong to combine properly. 

If the soap boils up high and thick, and a sample is ten¬ 
acious on the trowel, water must be evaporated to shorten it. 

If it is very clear and tough, and a cold sample is very stiff 
and rubber-like, salt or brine must be added, according as more 
water may be needed. 

If the soap contains too much salt, more cocoanut oil and 
lye will have to be added. Too much salt makes the soap rough 
and brittle, and if the excess is very great, may even cause it 
to settle. 

A properly finished soap of this kind is clear and has a 
bright surface; the steam of the evaporating water escapes from 
numerous places all over the surface (called “roses” in Ger¬ 
many, owing to the similarity of the formations to this flower) 
and a sample on the paddle must have enough consistency while 
still hot not to spread out very much; when sliding off the in¬ 
clined paddle it must break off short, and the paddle can be seen 


226 


Eschweger Soap. 


Proper quality of 
lye for Esch¬ 
weger. 


in places between the clots of soap; a slight sharpness should 
also be apparent. 

The lye used in saponifying the fats may be of high-grade 
caustic at first, and the required salt and carbonate of soda 
added after the materials are thoroughly combined, or the salts 
may be added from the start. A close study of the lye used is 
necessary in making this soap, and careful observation and con¬ 
siderable practice are required before it can be made with uni¬ 
form success. The presence of various salts is of far-reaching 
effect, and, unless the nature of the lye used at the outset is well 
understood, it will be next to impossible to form a correct idea 
of what salts must be added. 

If too little lye or salt is used, the soap will be soft and 
tough, instead of short, thus making it spotted throughout, in¬ 
stead of mottled, if framed in that condition. If too little water 
is used (or the soap evaporated too much) it will also be spotted; 
with too much water the mottle will form badly, or the soap will 
even separate a nigre. The presence of too much salt causes the 
soap to feel wet and cold while fresh, the mottle has a bad ap¬ 
pearance, and on drying the soap effloresces strongly, and be¬ 
comes rough and brittle. 

If a very caustic lye has been used at first, the apparent 
sharpness sometimes disappears when the salts are added, thus 
indicating that the fats were not fully saponified. In such case, 
more lye must then be added. 

If very* caustic lye has been used, solutions of carbonate of 
soda (sometimes silicate of soda) are added during the boiling, 
or the lye is made at once by dissolving 20% of soda ash with 
the high-grade caustic. As the various foreign salts are unable 
to form a chemical combination with fat, they merely contribute 
to give the soap the required mobility to permit crystallization 
(and consequent mottling) in the frame; they also prevent the 
finished soap from drying out too rapidly, and, of course, also 
increase the yield of soap. 

As was observed under “ boiled-down ” soaps, a pure tallow 
or olive oil soap must be brought into proper condition (/. its 
toughness reduced) by traces of salt introduced in the boiling- 
down operation in order to enable the stearate of soda to crystal¬ 
lize and form a mottle; at the same time, such soap holds but 
very small quantities of salt. Pure cocoanut oil soap, however, 
is quite different, for it forms a tough solution even in the pres- 


Eschweger Soap. 


227 


ence of quite considerable amounts of salt and water, of which a 
large quantity is required to cause the right consistency for 
mottling - —so much, in fact, that a mottled soap made from 
cocoanut oil alone could scarcely be referred to as “pure” soap 
in the true sense of the word. Thirty to thirty-five pounds of 
cocoanut oil to 100 of tallow, or similar fats, furnishes a good 
product which is much liked in some localities, and forms a beau¬ 
tiful mottle. 

A soap having very little sharpness, only little water, and a 
correct proportion of foreign salts, inclines to a large mottle. 
A smaller mottle results if the soap is somewhat sharper and 
contains somewhat more water, provided again that sufficient 
foreign salts are also present. 

No hard and fast rule can be given, what kind and how 
much salts to add; a trial will determine this, according to the 
composition of the fats and lye and the nature of the soap intended 
to be made. Ordinarily, lye made from low-grade caustic is 
used to supply the necessary carbonate, and the final corrections 
made with salt dissolved in water. 

Many, however, prefer to use high-grade lye for saponifica¬ 
tion, adding from 15 to 20% silicate of soda, either at once or 
after the materials have joined; then the soap is shortened by 
adding say 3% of soda crystals, and the final correction is made 
with a solution of common salt, until the required appearance in 
the kettle indicates that the soap is well made. 

Carbonate of soda —either present in the lye, if made of low- 
grade caustic, or added afterwards—causes a beautiful mottle 
and a high yield of soap. But if used as the only salt, the soap 
will incline to effloresce or “ whitewash,” especially in winter. 

Carbonate of potash, substituted for part of the soda, avoids, 
or at least decreases the latter difficulty, but the marble formed 
will be less beautiful. 

Common salt causes a very fine mottle, but the soap will bind 
less water and the yield will be correspondingly less from a 
given amount of fat. 

Silicate of soda thins the soaps, and if used, less of the other 
salts must be employed, so that there is really no gain in using 
it for this soap, except in that, while the yield is not as large at 
first the soap also does not dry out as much afterward. When 
it is employed for this soap the lye should be more caustic than 
when sal soda is added instead, and the soap should have a slight 


Large and small 
mottle. 


Effect of various 
salts. 


228 


Eschweger Soap. 


vOloring matter. 


Framing. 


Boiling by steam. 


sharpness to guard against the silicate crystallizing out. As 
high as 30 per cent may be worked into the soap, but 15 to 20 
per cent gives a better product and is safer against irregulari¬ 
ties in boiling. (Soaps of similar composition as to fats—not 
mottled—are sometimes filled by boiling in this manner with as 
much silicate—diluted previously by boiling with water—as the 
weight of the fats used.) 

The less cocoanut oil enters into the soap, the less water 
and salts must of course be added, and the smaller will be the 
gain in soap. 

When the soap in the kettle shows by the appearance de¬ 
scribed that it is in the right condition, the desired color (cop¬ 
peras, ultramarine blue, Indian red, etc.) stirred into boiling 
hot water to which a little salt has been added, is put into the 
soap, and well boiled through with open steam until the color 
is uniformly distributed. 

The salt is added to the color in order to prevent it from 
clotting together; strong lye might be used instead if the con¬ 
dition of the soap is such as to make it preferable. It is well to 
take a sample of the soap out of the kettle and see if the color 
mixes with it evenly; if not, more salt must be added. The soap 
and coloring mixture should both be as hot as possible, in order 
tu be readily mixed. 

The amount of coloring matter to be used, it must be under¬ 
stood, has no effect on the quantity or formation of the mottle; 
it only affects the intensity of its color and must be gauged ac¬ 
cordingly. 8 to 10 lbs. of Venetian red to an ordinary frame 
will produce a good effect. Other colors, which may'be used in 
proportions according to their nature, are Indian red, ultra- 
marine blue, ivory black, etc. 

This finishes the boil, and the soap is run into the frames, 
where it is crutched for a short time and covered up to keep it 
warm. In the course of three hours, if the marble is seen form¬ 
ing, the frames are uncovered and the soap allowed to cool. 
Wooden frames are best employed in this case, in order to avoid 
chilling the soap on the sides. 

This soap is made mostly (in Germany) over an open fire, 
but this affects its color disadvantageous^, and the soap may be 
boiled as readily with closed steam at a pressure of 3 to 4 atmos¬ 
pheres by managing the lye so that no excess of water is present 
that requires evaporating. 


Eschweger Soap. 


229 


In making- this soap a record should be kept of the grade of 
caustic used and the quantity and kinds of salts added; these 
notes will then serve as a g-uide for the next batch until more 
practice has been obtained. If the soap mottles properly, but 
effloresces on drying-, the lye for the next boil should be used 
more caustic, and more potash and salt used instead of carbonate 
of soda. 


BLUE MOTTLED OR E5CHWEQER III. 

A soap made as described, of about one-third cocoanut oil 
and two-thirds of other fats, with a yield of 200 to 215 lbs. 
of soap from 100 lbs. of stock, is considered as Eschweg- soap 
proper. If, however, the fat used consists nearly all or entirely 
of cocoanut oil or palmkernel oil, and the soap is shortened with 
various salt solutions until it is in proper condition to form a 
mottle, the yield will be increased to 300 to 350 per cent and 
more. Such soaps, which were first broug-htout in Eng-land and 
whose method of manufacture was g-uarded as a secret for about 
ten }^ears, are hardly ever made in this country, but are quite well 
known in most other countries where they are variously sold as 
“blue mottled,” “Eschweg- III.” etc. They are g-enerally con¬ 
sidered still more difficult to manufacture with uniform success 
than Eschweg- soap proper, and in most cases are the dread of 
those to whose lot it falls to be oblig-ed to make them, for all are 
agreed that these soaps require very much attention and patience, 
and even then will be failures at times in the hands of the most 
experienced. We will briefly describe the averag-e process; as 
there is a very larg-e number of different proceeding's in vog-ue: 

Tnese soaps are made most frequently by half-boiling, the 
fat being- saponified at a temperature of about 190- F. and the 
soap formed in the course of several hours’ rest in the kettle is 
then filled with the necessary salt solutions. However, boiling- 
the fat and lye before filling- until thoroug-hly saponified would 
prevent many failures in the process, as they are most common¬ 
ly only the result of free fats being- present, and soap so made 
would dry out less than when the stock had not been perfectly 
saponified. For the proper formation of the mottle in these 
soaps every soap-maker adheres very closely to certain proportions 
of materials which he has found by experience to g-ive the desir¬ 
ed result, and at the close of aboil carefully watches small sam¬ 
ples taken from the kettle, to see if any corrections are required. 


\ 


Definition fb 
Eschweger III* 


Boiling vs. 
boiling. 


230 


Eschweger Soap. 


Both palmkernel oil and cocoanut oil lend themselves well 
to the manufacture of these soaps; the latter especially permits 
of high filling and calls for slightly more lye and salt solution. 
The general proceeding is the same for either oil. 

The following formula will serve as an example: 

100 lbs. cocoanut oil. 

130 lbs. caustic soda lye 24 ~ B. 

20 lbs. sal soda. 

42 lbs. salt water 23° B. 

20 lbs. potash solution 30° B. 

The cocoanut oil is saponified with the lye at a temperature 
of 190° F. and when the materials have joined, some of the salt 
water is added, enough to prevent thickening. 

(Or the fat may be saponified by boiling, in which case the 
water lost by evaporation must be restored, and the salt solutions 
are then rapidly crutched in when the soap has cooled down 
somewhat). 

Next the potash solution, then the sal soda, and lastly the 
remaining salt water is crutched in and the temperature main¬ 
tained for some time at about 200° F., covering the kettle and 
occasionally crutching through. 1)4 ounces of ultramarine blue 
are then dissolved in 4 lbs. of water to which 4 lbs. of silicate of 
soda and 1 lb. 25° B. caustic soda lye are then added. A small 
portion of the coloring mixture is added to the soap, and samples 
taken. (Or a 20 lb. sample of the soap is taken and some color 
added for the test, before coloring the soap in the kettle.) If 
the silicate is observed to crystallize or form flakes, a little more 
lye must be very carefully added to the coloring solution until it 
will mix easily and uniformly with the soap. The kettle, after 
coloring, is covered for an hour, when samples are taken out. If 
the soap is then uniformly colored blue, it has too much strength, 
and some cocoanut oil must be added, and time allowed before 
another sample is taken out. If the mottle has, on the other 
hand, been formed rapidly and in long streaks, the soap is weak 
and requires a little more lye. When samples appear satisfactory 
(they should be preserved for comparison with later batches), 
the mottle appearing in small dots, the soap is framed at 165 to 
170° F. and the frames kept covered for the first hour or so. 
While the soap cools down to this framing temperature, it is ad¬ 
visable to have a bucketful of the soap cooling off separately, so 
as to judge by it if it is safe to frame the batch, without crutch- 


Eschweger Soap. 


231 


ing it up first; in large frames the mottle will then be still prettier. 
The frames used have a capacity of from 1,200 to 2,000 lbs. 

A good way to judge whether the soap is right for mottling, 
is to take out three or four samples of 10 lbs. each, and adddif* 
ferent small proportions of cocoanut oil to the samples, and cover 
up for half an hour. According to the mottle formed in this 
time in the different samples it may be seen whether oil should 
still be added into the kettle, and how much. 

If the mottle forms in the frames, but drops to the bottom, 
it may be brought up by crutching, provided the soap has not 
yet cooled below about 14CG F., as it will form again. A weak 
soap mottles most readily, but inclines most to dropping the mottle 
in the frames; it is therefore best, when judging of the samples, 
not to go entirely by the most beautifully mottled sample. A 
somewhat strong soap forms a smaller mottle which is not liable 
to drop, but sometimes requires to be covered in the frame for 
several hours in order to prevent a bluish tint in the portions in¬ 
tended to be white. 

Another formula is as follows: 300 lbs. palmkernel oil are 
saponified with 360 lbs. 20° lye; there is then added, under brisk 
boiling, a filling mixture consisting of 70 lbs. 25° soda ash so¬ 
lution, 70 lbs. 25° potash solution, 17 lbs. 20 potash lye, 120 lbs. 
20" salt solution, 80 lbs. water; the kettle is then covered and 
left at rest; samples are then taken to test for mottling and, if 
satisfactory, the coloring is added as above. As palmkernel oil 
varies somewhat, it may be necessary to increase the lye from 
360 lbs. to 375 and even more. In hot weather, when it might 
happen that the soap settles, owing to being liquid too long, it is 
advisable to have it somewhat sharper in strength than in 
winter. 

For the benefit of readers in foreign countries where these 
soaps are made, we append, from the notes of a soapmaker who 
has made them extensively, the following table of proportions of 
materials which have proved satisfactory for the yield indicated 


in each case : 

Palm Kernel Oil.100 100 100 80 60 parts. 

Cocoanut Oil. — — — 20 40 “ 

20° B. soda Lye.120 120 120 130 134 “ 

33 c B. Potash Solution. 45 53 80 90 110 

24° B. Brine. 55 70 90 120 143 “ 

Coloring. 5 7 10 10 13 







232 


Eschweger Soap. 


Genei'al remarks. 


(The coloring’ is composed of 4 parts 38°-40° waterglass, 4 parts 
water, 1 part 20° B. lye, one-tenth part Eschweg red or blue, or 
for grey, half blue and half black.) 

One other formula, among - hundreds of similar ones, may 
be here briefly mentioned, although it does not properly belong 
to boiled soaps: 

100 lbs. cocoanut oil at 190 c F., into which 
50 lbs. talc are stirred; add 

112 lbs. soda lye 20 c B. When saponified, add 
3 lbs. salt, dissolved in 
10 lbs. water, and next 
40 lbs. water glass, mixed with 
10 lbs. soda lye 36 c B. 

The manufacture of these soaps depends less on the exact 
formula used than on its proper manipulation, and considerable 
experience is the most essential feature in making them. Accord¬ 
ing to the proportions of the ingredients employed, a soap will 
form the mottle more or less rapidly, and the frames must be 
adapted in size to correspond. Small wooden frames of about 
500 lbs. capacity are best adapted for soap which forms a large 
mottle, and rapidly; such soap is framed at about 145 F., and 
should contain more salt water in comparison to soap which is 
run into large iron frames (up to, say 2,500 lbs.) to form the 
mottle more slowly. The latter should contain weaker and more 
carbonated solutions, and less salt water, and may be framed 
warmer than the quickly mottling soap. 

The several solutions mentioned for filling should be 
made sometime before use, so as to permit their settling where¬ 
by a whiter ground of the soap is obtained. They must be made 
from raw material whose composition (purity) the soapmaker is 
familiar with, as unsuspected impurities have been the cause of 
numerous failures. 

For soaps which are not to yield more than 350% some tallow 
is used with the cocoanut oil, as this favors the rapid mottling 
which is necessar} 7 when small frames are used. Cottonseed oil 
may also be used, in place of tallow. Cocoanut oil requires, in this 
class of soaps, more lye and salt solution than does palmkernel 
oil, and consequently gives a greater yield. 

A MODIFICATION OF ESCHWEGER. 

A soap similar in character to the “Eschweger” described 


Eschweger Soap. 


233 


but boiled in a manner approaching- nearer to the methods more 
usual in this country, is made as follows : 

The fats are selected and clarified in the same manner as for 
Eschweg-er. They are then saponified by running- in lye under 
constant boiling-, until the soap acquires a sharp taste which it 
retains on boiling- for a few minutes without the further addition 
of more lye. (This operation has been fully described in detail 
in the chapter on White Settled Soap.) More lye is then care¬ 
fully added in small portions, while boiling, until the soap sepa¬ 
rates from it. The supply of lye is then cut off and boiling is 
continued until by evaporation of water a very soft and large 
grain is formed, from which the lye will settle thoroughly and 
rapidly. 

If on continued boiling the soap remains separated from the 
l}’e (indicating that it has all the strength it can absorb), it is 
allowed rest to settle. 

The waste lye contains sufficient strength to require saving 
it for some other boil, and it is therefore no disadvantage if—ow¬ 
ing to the cocoanut oil—it should contain a little soap in solution, 
for in that case it will settle the lye most thoroughly; if the soap 
were grained out too strongly this would prevent the complete 
removal of the lye, which is very essential, and so much water 
would be required in the next operation that there would be dan¬ 
ger of the soap becoming too thin to hold the coloring matter 
suspended for mottling; the soap obtained would also be less 
neutral, and would shrink more on drying. If there should be any 
indication, therefore, that the waste lye has not settled so per¬ 
fectly that it can be drawn off entirely, a little cocoanut oil may 
be added afterwards and boiled through, to absorb the excess of 
strength. 

The lye is then run off, as is also any nigre that may have 
formed, and the open steam turned on. When the contents of 

m 

the kettle are again boiling, enough hot water is carefully 
run in to thicken the soap which is at first thin and stringy, and 
to form it into a tough, clear mass through which the steam es¬ 
capes with difficulty. (Instead of simple water a weak solution 
of silicate of soda (8° B.) may be employed. Up to 50 per cent 
silicate solution is sometimes used for such soaps in England.) 

It will be observed that the soap is now in a condition prac¬ 
tically identical with that of a finished “Eschweger” described, 
and the quality of lye used, the various signs indicating the pro- 


234 


Eschweger Soap. 


per conditions, and the remedies employed in certain irregularities 
are also the same. 

When the color has then been well incorporated the soap is 
framed and covered up to form the marble. 


CHAPTER X. 


> 

Soft (Potash) Soap. 


General Remarks. 

When, instead of the soda, potash only is employed for saponi¬ 
fying - the fats, the resulting - soap is very much softer than are 
the hard soda soaps; especially if the stock at the same time 
consists of the softer oils, in place of the more solid fats rich in 
stearin, the product will be a soap of about the consistency of 
lard—a true “soft soap.” (There have lately been patented in 
several countries special methods of making hard potash soaps 
which contain only about 10% of water, but these do not come 
under our consideration at present). 

In this country soft soap is but little used outside of the tex¬ 
tile industries, but in most other countries it has an enormous 
sale also for household purposes, such as cleaning floors and 
woodwork and for rubbing on clothes in the laundry. Its un¬ 
equaled solubility and handy form have made it a favorite soap 
many places, especially so since the evil smelling fish oil, and 
also the somewhat less obnoxious linseed oil, which were former¬ 
ly used largely for soft soap, have been supplanted by cotton 
seed and other oils which furnish a soap of less unpleasant odor. 

A soap made of oil and potash lye alone is not only the ^oap! 1 ^ 01 ° U 
most readily soluble of all, but also the only kind which is per¬ 
fectly soluble in cold water. Owing to this great solubility, 
its soft consistency, and to the excess of alkaline strength, caus¬ 
tic and carbonated, which it ordinarily contains, it saves much 
time and labor. Its peculiar value for the treatment of fabrics, 
and especially woolen goods, has already been pointed out un¬ 
der the heading of “ Textile Soaps ” (page 176), while it is also 




236 


Soft Soap. 


Requirements 
soft soap. 


well adapted for some toilet purposes, if properly made. As a 
basis for medicated soaps likewise the soft variety is frequently 
preferred to hard soap. 

The manufacture of a soft soap that answers all the demands 
of the consumers is in most cases a somewhat complicated mat¬ 
ter, for the requirements are numerous and varied, and not always 
easily made to correspond with that ever present enemy of soap 
makers—cheapness. Besides the special requirements depend¬ 
ing - on the class of work to which the soap is to be applied, there 
of are a few general properties which are more or less looked for 
in every soft soap, as follows: Its consistency and composition 
must be such that it does not become too liquid in hot weather, 
so as to run, nor become brittle or freeze in winter; in fact, its 
composition must be adapted to the season; it must have a good 
body at all times and yet feel unctuous; it must be “short,” so 
as not to draw threads on removing a portion, but on the other 
hand it must not be wet and slippery; it should possess a cer¬ 
tain degree of transparency and a good color, and—if a figged 
soap—the grains of potassium stearate must be formed in size 
to conform to the prevailing taste of the customers. That the 
production of a soap of these characteristics is an operation re¬ 
quiring considerable attention is evident from the fact that even 
so apparently trivial a matter as repeatedly taking small quan¬ 
tities of the soap out of a barrel with wet hands is sometimes 
sufficient to render the remaining soap stringy. 

The conditions which operate to form a soap answering the 
above description rest, briefly stated, on the selection of fats of 
suitable consistency to adapt the soap to the season; on the use 
of lye containing a proportion of carbonate or other potash salts 
which, as they do not combine with fat, serve to insure the re¬ 
quired shortness; and on the right amount of alkali and water 
in the soap. In this connection it may be mentioned that soft 
soaps contain, as a rule, more water than the good qualities of 
hard sonps, and that a larger quantity of potash is required to 
form a neutral soap with a given amount of oil than would suffice 
if the alkali used were soda, to say nothing of the excess of alkali 
which is present in all ordinary soft soaps. 

A perfectly neutral compound of oil and pure caustic potash 
forms a turbid, gummy, sticky mass, which becomes a salable 
soap only by the further addition of a solution of caustic and 
carbonated potash. While for a hard soap are required about 


Soft Soap. 


237 


100 to 120 lbs. 20 u soda lye for every 100 lbs. of stock, there are 
required for a soft soap 155 to 170 lbs. of (partly carbonated) 23 
*—24 potash lye. Considering* furthermore that soft soaps are 
made by simply boiling* the fats and oils with the lye, without 
any separation of waste lye and glycerin, it will be seen that 
the yield of soft soap from a given amount of fat is considerably 
above that obtained in hard soaps. We shall refer again to the 
question of yield further on. It is seen from this that the ordi¬ 
nary soft soap differs from hard soaps not only in the nature of 
the alkali with which it is made, but also in its larger propor¬ 
tion of water and free caustic and carbonated alkali. In fact, 
soft soap is frequently described as being a neutral soap dis¬ 
solved in an aqueous solution of caustic and carbonated potash. 

As to the stock used, this may be train oil, linseed oil, cot- stock for soft 
ton seed oil, red oil, olive oil, rosin, with or without the addition 
of tallow or other fats rich in stearin. In winter thin oils are 
preferred, but in summer the addition of cotton seed oil, tallow, 
or some other stock forming a more solid soap, is necessary to 
secure the product from becoming too soft. Train oil, and to 
a less degree also linseed oil, have the disadvantage of furnish¬ 
ing soap of unpleasant odor which even strong essential oils 
(mirbane, etc.) fail to disguise effectually. But linseed oil has 
the advantage of rendering the soap proof against low tempera¬ 
tures if made with pure potash lye; in summer it requires part 
soda lye, without the aid of which the soap would be too soft in 
warm weather. Rosin is also much used, especially in brown 
soap, and gives it a tine, bright appearance. As it makes the 
soap softer, less should be used in summer than in winter, ana a 
little more soda lye should be used to counteract its tendency to 
soften the product. 

Regarding the lye used in these soaps we refer the reader to Lye for soft soap. 
Chapter III, and also to the remarks on that subject under 
“Eschweg” soap, which apply largely to soft soap as well, es¬ 
pecially to “ figged ” soap. In case pure caustic potash be used 
for making* the lye, it will be necessary to add about 26 to 28% 
of the weight of caustic, more in winter than in summer, of car¬ 
bonate of potash or chloride of potash toward the end of the 
boiling, to shorten the soap; but it is preferable in practice 
to begin with a lye alread}^ containing most of the salts 
from the start, and only adding at the finish the small am¬ 
ount that may still be’ wanting. In summer some of the pot- 


238 


Soft Soap. 


Coloring. 


Filling. 


ash is substituted by soda, so as to give the soap a greater con¬ 
sistency; too much soda lye, however, or the chlorides of soda 
and potash, make the soap appear turbid. In hot weather from 
one-quarter to one-third of soda may be employed in place of an 
equivalent amount of potash, but allowance must, of course, be 
first made for the soda, with which much of the commercial pot¬ 
ash is contaminated. If the lye used be too caustic, the soap 
boils thick and heavily, remaining at the bottom of the kettle 
instead of rising, and samples of the soap appear tough on run¬ 
ning from the paddle, and are of a hard or gummy consistency 
when cold; in that case some carbonate of potash solution must 
be added, until the soap runs off the paddle very short (in win¬ 
ter) or draws threads not longer than l / 2 inch (in summer). On 
the other hand, if the lye is not caustic enough, so that too 
much of salts are introduced, the soap boils up very high in the 
kettle, boils over readily, appears watery, and lacks consistency, 
so that a sample placed on glass spreads very much. To remedy 
such a case pure caustic lye and more stock must be added. 

For coloring soft soaps there are used palm oil (for yellow), 
rosin or sugar color (for brown), and ultramarine blue or indigo 
(finely powdered and previously boiled for a considerable time in 
water and lye) to give a green color. 

Of course, there have also been found ways to fill soft soaps, 
which may be briefly referred to here: The filling mostly used 
is a solution of potassium chloride in water (14° B.), of which 
about 1 lb. is crutched into the cool soap (at 160 to 170° F.) for 
every 5 lbs. of stock used. To take this filling well, it is easily 
understood that the soap should be made with a comparatively 
caustic lye rather than with one containing much carbonate. If on 
adding this filling the soap becomes turbid, it is a sign that caus¬ 
tic strength is lacking. Neutral soft soaps can absorb, dissolve 
as it were, certain quantities of various salts and water, and }~et 
remain perfectly clear. That this property is due to the salts 
in the filling is shown by the fact that if say 15 lbs. of simple 
water were added to 100 lbs. of a well-made soft soap, the pre¬ 
viously clear and solid soap would turn soft, turbid, and long, 
as soon as it is cooled, while the crutching in of a like amount 
of a suitable salt solution will leave the soap clear and of good 
consistency. It is to be observed here that in warm weather the 
soap remains clearer with thin solutions than in the cold; the 
lower the temperature of the atmosphere the stronger must be this 




Soft Soap. 


239 


kind of filling - . All potash salts can be used for this purpose 
with about the same effect, but potassium chloride is usually pre¬ 
ferred to the carbonate or sulphate for its cheapness, ready solu¬ 
bility and convenient use. It can be added during the boiling 
or afterwards, and shortens the soap more than does pearlash. 

Some soapmakers prefer the sulphate of soda, as it softens 
the soap less; this is the result of some soda soap forming in the 
kettle when sulphate of soda is used, and this soda soap gives 
greater consistency to the product; but the same result could be 
obtained more cheaply by using some soda lye in the boiling in the 
first place and then filling with potassium chloride as just described. 

Another favorite material is potato flour, rice flour, or starch, 
because the same bind considerable water and lye and thereby 
make the soap more solid, which may be even of advantage in 
hot weather; but at the same time the soap will be less clear 
and transparent when filled with flour. In combination with 
silicate of soda, starch is used in a manner as follows: Equal 
weights of starch, silicate of soda, and water are well stirred 
together; enough of the soap is then crutched in to make a 
creamy mixture, of which the desired quantity is crutched into 
the soap in the kettle. After adding this filling the soap has 
lost its “short” character, and requires the careful addition of 
some strong caustic lye (30° B.). Silicate of potash, diluted with 
water, is another suitable filling material for soft soap of which 
(at 18° B.) 25 lbs. may be used for every 100 lbs. of stock em¬ 
ployed; or a filling mixture containing this filler may be made 
of 10 lbs. silicate of potash, 15 lbs. potato flour, 20 lbs. potash 
solution of 12° B., 5 lbs. water and 5 lbs. potash lye of 28° B.; 
in using this filler, the proceeding is as follows: The potash so¬ 
lution, water, and flour are mixed together separately; into this 
is stirred some of the soap until a thin mass is obtained; the 
silicate and lye are mixed together and added to the soap in the 
kettle and well crutched through, then the flour mixture is 
crutched in, and lastly, when all is well mixed, some caustic lye 
for shortening will be required. Most fillers render the soap 
shorter, so that the latter should be made from the start with 
rather caustic lye, in order to have the right consistency after 
filling. Besides the materials just mentioned there are also used 
carbonate of soda (and of potash), and sulphate of soda. The 
peculiar action of soda salts on potash soap has been previously 
explained. (See also Appendix, Note 11.) 


240 


Soft Soap. 


Rosin. 

soap. 


Yield of On the effect of rosin, the different lyes, and the yield of 
soap (without filling-), a German writer made the following in¬ 
teresting observations: 

“ It may be called a rare occurrence for a soaprnaker to ob¬ 
tain the same percentage of yield in making several boils of one 
kind of soft soap. In a great majority of cases, even with the 
same fats and lyes, a difference amounting to several per cent will 
be noticed. The principal cause of this difference is the impossi¬ 
bility of adjusting with mathematical correctness the evaporation 
of water by boiling; what is ordinarily termed “ normal ” evapor¬ 
ation fluctuates between limits which account for these vari¬ 
ations. If the evaporation of water by boiling is sufficient in 
itself to bring about this result, it is still further explained on 
considering that the yield is affected also by the fats, by the 
greater or less causticity of the lye, and by the addition of soda 
in soap for summer use. 

“Among the unfilled soft soaps in which potash lye exclus¬ 
ively has been used, the “natural grain” (figged) soaps are 
prominent, in making which potash lye only is used in all sea¬ 
sons. The different fats selected for the different seasons do not 
influence the yield to a degree worth mentioning, as it is not so 
much the tallow but especially the oils which vary. Generally 
one-third tallow (figured on the total of fats) is sufficient, as, 
for instance, in summer sufficient stearin for the proper forma¬ 
tion of the grain is introduced by the increased proportion of 
cotton seed oil employed. The yield of linseed oil and of cotton 
seed oil may be assumed to be the same; the change in the pro¬ 
portions of these two oils used therefore has no practical influ¬ 
ence on the amount of soap produced. 

“The variations frequently enough encountered in the yield 
of these soaps generally fluctuate between 235 and 240. This is 
owing principally on account of stronger evaporation of water 
in the case of the lower figure named, for in these soaps espe¬ 
cially the manufacturer is careful to add potash solution if neces¬ 
sary to counterbalance great causticity in the lye. 

“ The proper degree of evaporation is recognized in such 
soaps by observing the froth on the surface toward the end of 
the boiling. When the soap, having been properly made with 
caustic and carbonated lye, falls in the kettle during strong boil¬ 
ing, this is the sign that the excess of water is removed and 
that boiling must be discontinued shortly after. If no formation 


Soft Soap. 


241 


of froth is then observed on the surface when th e soap has quieted 
down, we are justified in assuming’ that the soap was boiled 
down too strongly. (These remarks are based on boiling over an 
open fire, the excessive evaporation of water being here caused 
by either not drawing the fire soon enough, or by after-heating 
by the heat in the furnace, etc.) In this case the yield would 
probably fall short of 240 per cent, and in fact there is no clue as 
to how much water has been unnecessarily evaporated; it is then 
necessary for the proper yield to add so much water during slow 
boiling until a very little speck of froth—about the size of a 
5-cent piece—is seen on the surface. This affords a certainty 
that the proportion of water is neither too high nor too low; still 
there will be small variations in the weight as frequently more 
or less froth is caused, which, however, does not influence the 
quality of the soap and therefore requires no correction if the 
variation is not too far from the normal condition. 

“Greater differences in the yield occur in the unfilled ordi¬ 
nary smooth and green soaps (Crown soaps), this being a natural 
consequence of the changes in the proportions of rosin used and 
in the lyes employed. The yield of soap decreases in proportion 
as more soda lye is used, as less soda is necessary to saponify the 
oil than is required of potash. Soft soaps made of pure potash 
lye show a larger increase, for in a case requiring 56 parts potash 
lye for saponification, 40 parts of soda lye of the same strength 
and causticity would be quite sufficient. Then the character of 
the lye plays an important part in the yield. Of a very caustic 
lye less is, of course, required to saturate the oils than of one 
containing more carbonated alkali, for it is the caustic lye alone 
which saponifies oils, while the action of the carbonated alkali 
is purely mechanical and by its presence naturally increases the 
yield. 

“According to season the smooth and green soft soaps con¬ 
tain more or less rosin. The yield is in these cases figured on 
the basis of the fats alone, because on account of its low price 
the rosin is considered as belonging rather to the filling than to 
the fats. 

“ One would think that the lye required for saponifying the 
rosin would add to the yield of soap in the same proportion as 
in pure‘oil soap, but when the rosin is boiled together with the 
oils from the start, it rarely causes an increase above its own 
weight, compared to the soap made without rosin. For example 


242 


Soft Soap. 


1,500 lbs. linseed oil and 225 lbs. rosin (15%), without using 
any soda lye, furnished, according- to repeated weig-hing-s in act¬ 
ual practice, 3,600 lbs. soap; this is 240%, figured on the 1,500 
lbs. of oil. The same result was obtained when 1,200 lbs. lin¬ 
seed oil, 300 lbs. cotton seed oil, and 225 lbs. rosin were used. 
Only once a percentag-e of 242% could be recorded. If now a 
pure oil soap, (without rosin and soda lye) is considered as yield¬ 
ing- 228%, then the 1,500 lbs. of oil would yield 3,420 lbs. of soap, 
and if we add to this merely the simple weight of rosin we have 
3,645 lbs. or 243% ag-ainst 240% actually yielded. The explan¬ 
ation ©f this deficiency can only be found in the strong-er boiling- 
down required for soaps containing- rosin. The indications show¬ 
ing when enough water has been evaporated are the same in soap 
made with rosin as in those without rosin, but in the former 
they appear later, thereby causing the lower yield. 

“ Several boils with 10% rosin, made without soda lye, gave 
a yield of 236 per cent. The materials were 1,250 lbs. linseed 
oil, 250 lbs. cotton seed oil, 150 lbs. rosin. 

“The same soaps with only 5% rosin, made in the same 
manner, yielded from 230 to 232%. Small variations occur here 
also, because the lyes are never quite alike, nor is the degree of 
evaporation. 

“ The yield of summer soaps, as already said, depends on 
the use of soda lye. In this respect the use of the cheaper cotton 
seed oil is of advantage, for with the addition of but little soda 
a sufficiently solid soap results, together with a larger yield. In 
the very hot season cotton seed oil may be used almost entirely 
for smooth soft soaps, when of course the soda lye must be entire¬ 
ly omitted. In less warm weather half linseed oil and half cotton 
seed oil with 5 to 10% rosin, may be used, but it may then be 
well to use from 8 to 10% of soda lye to guard the soap against 
becoming too thin. The loss in the yield with so little soda lye 
will not be more than two or three per cent. 

“ In calculating the yield in the case of filled soaps it is only 
necessary to subtract the weight of filling used and divide the 
weight of actual soap by the weight of the oils used, to get the 
percentage of yield. For instance, if 1,250 lbs. linseed oil, 250 
lbs. cotton seed oil, and 150 lbs. rosin, with the aid of 380 lbs. 
chloride of potash solution, make 3,920 lbs. of soap; then there 
are 3,540 lbs. of real soap, and this divided by 15 (1,500 lbs. of 
oils) =236%.” 


Soft Soap. 


243 


Thk Boiling. 

The boiling- is carried out either in a steam-jacketed kettle 
or by the aid of closed and open steam pipes. Towards the 
finish a considerable degree of heat is required, for which reason 
the use of closed steam alone would require considerable pressure 
in the boiler. At all events, the kettle must be placed as near 
as possible to the boiler, so as to avoid the cooling of the steam 
while it is conducted from the boiler to the kettle. In other 
countries an open fire is used almost exclusively, but this is very 
liable to burn the soap. 

The manufacturing process of soft soaps is almost as varied 
as in the case of hard soaps. If rosin is used, it may be melted 
with the oil and both saponified together, or the rosin is added 
with the necessary lye of 30° B., after saponifying the oil, and 
the whole boiled together. The proportion of rosin in any soft 
soap should not exceed 1 lb. to 10 lbs. of stock. The lye may con¬ 
tain the necessary carbonate from the start, or it may be caustic 
and the soap shortened afterward with pearl ash and chloride of 
potash solution, as said before. 

Other points of variation will appear from the following de¬ 
scription of the processes adopted for different soaps. 

CROWN SOAPS. 

“Crown soap” is one of the many names by which those 
soft soaps are known which are homogenous throughout, as 
distinguished from the “ figged ” soaps, which have numerous 
small crystals of stearin soap distributed throughout the mass. 

The lye is made either by dissolving commercial caustic pot¬ 
ash in water or by causticizing the carbonate. The first-named 
method is the easiest and safest, as it makes a more uniform lye. 
The causticizing of carbonate of potash is done as follows: The 
potash is dissolved in water, by means of heat, until it shows 20° 
B. For every 2 lbs. potash there is then added about 1 lb. of 
freshly-slacked lime and the whole boiled for an hour, when the 
lime is allowed to settle until the lye can be drawn off clear. 
The precipitate is heated again, with more water, to make lye 
of about 12° B. A third washing (anything less than 10° B.) is 
reserved to be used instead of water for dissolving the next batch 
of alkali. As the potash and the lime are of ever-varying degree 
of purity, this process of making the lye is liable to prove trouble¬ 
some in the boiling of the soap, especially to the inexperienced 


Boiling by steam. 


Causticizing pot 
ash. 


244 


Soft Soap. 


Stock. 


soap-maker. For making- a purer lye, the potash may be dis¬ 
solved at first to form a 40° B. solution, from which the impurities 
are settled out, the foreign salts crystallizing- out and settling to 
to the bottom or attaching- themselves to the sides of the vessel. 
The purified solution is then diluted to 20 B. and causticized as 
above. 

As to quantity, there are required about 36 lbs. of pearl ash 
(causticized with lime), or in other words, about 160 lbs. 24 B. 
lye for 100 lbs. of stock. Of low-grade potash, or when the soap 
is to be filled, somewhat more is required. 

The stock for these soaps may be linseed oil, cotton seed oil, 
red oil, and grease, in porportions to suit the manufacturer, and 
the season, and of course also rosin, if desired. With much lin¬ 
seed oil about 1 part soda lye may be used with every 2 parts 
potash lye in summer; the more grease is used, the less soda lye 
is admissible. In winter the soda lye is omitted altogether. The 
stock may be run into the kettle the evening previous to boiling 
the soap, together with say 40 lbs. of lye for every 100 lbs. of 
stock, and well mixed. Not much more lye, however, must be 
taken for this purpose, as otherwise the soap may- set in the ket¬ 
tle. Nor must the materials be mixed too warm or the spon¬ 
taneous development of heat might cause boiling over. If the lye 
had been made by dissolving a pure grade of caustic potash, and 
it is intended not to add the required carbonate until the finish, 
and to boil with open steam, the lye may be used from the start 
at a strength of 20-24 B., but if the lye had been made by caus- 
ticizing the carbonate in the soap factory (and therefore contains 
the carbonate intended to be in the soap), and if is were intend¬ 
ed to boil over an open fire, the weakest lye obtained in caustic- 
izing (10-12 B.) must be used at first, using the stronger lye as 
saponification progresses. In other words, the strength of the lye 
is regulated in accordance with its caustic strength and with the 
amount of water required, so as to avoid the necessity of evapo¬ 
rating much water at the finish. The materials begin to com¬ 
bine over night, and next morning steam is turned on. When 
the contents of the kettle come to a boil, the remaining lye is 
run in gradually, under constant boiling, so as to be all in the 
kettle at the end of about one hour. During this time the soap 
must not be allowed to become weak, to prevent bunching. The 
soap now soon becomes clear, indicating that the stock is fairly 
well saponified. Small samples are the’n set on glass, to see if 


Soft Soap. 


245 


the soap has all the necessary characteristics of a well-made soft 
soap. The sample will probably be thin, and on touching- it 
with the fing-er it will draw a thread; on cooling- it will lose its 
transparency, and be jelly-like in consistenc} T ; on the surface of 
the soap in the kettle there may be a lig'ht scum. These sig-ns 
indicate that there is an excess of water which must be evapor¬ 
ated in order to “shorten” the soap, by boiling- for a while long-er. 

If the sample is not clear, and is slippery on the glass, it shows 
an excess of streng-th, which can only be remedied by adding- more 
stock. If the sample is clear at first, but becomes gray in the 
center on cooling, lye is wanting. 

The soap which is finished correctly appears as follows : Sl ^" i s h ° f pi ’ oper 
While boiling, it suddenly falls in the kettle, the water having 
evaporated just sufficiently to shorten it enough; the soap in the 
kettle is clear, with very little or no froth on the surface, and 
the boiling mass opens in “roses” similarly as described under 
Eschweg soap. A heaped sample on glass does not spread very 
much and shows few air bubbles; touched with the finger it draws 
no thread, but merely forms a very small point; it is clear, and 
on cooling becomes surrounded by a very narrow grayish rim of 
lye, covered with a fine striped skin. (This latter appearance is 
termed “lye flower” by the German soap makers, and is the re¬ 
sult of the evaporation of the water from the hot sample, by 
which the latter appears as if evaporated too far.) In the sum¬ 
mer the soap should be made less strong, and the sample should 
therefore have this striped appearance less strongly developed 
than in winter, when a little extra strength protects the soap 
against freezing 

If the samples have the required appearance, the soap is fin¬ 
ished—unless rosin is to be added, in which case it is broken 
fine, thrown into the soap, and boiled, together with the necessary 
quantity of 30° soda lye, until the appearance of a sample, as be¬ 
fore, indicates that it is finished. 

The soap is allowed to cool in the kettle to 150 F. and then 
run into barrels, and crutched until cold.. 

FIGGED SOAPS. 

By appropriate manipulation soft soap can be made so that 
in course of storing it for a time it develops numerous crystals of 
stearate of potash throughout the mass, ranging in size from 
that of a pin-head to that of a grain of rice, giving it a “figged” 


246 


Soet Soap. 


Stock. 


appearance much liked by consumers. This process of crystal¬ 
lizing- is analogous to the formation of the mottle in hard soaps, 
but requires long-er time, taking- from two to six weeks. It is 
broug-ht about, in the first place, by the addition to the stock of 
some fat rich in stearin, such as tallow, for the formation of the 
grain; for the clear body of the soap oil is used. The lye used is 
potash altog-etlier, without the addition of any soda lye, and even 
the potash should be as free from soda as possible, as the latter 
prevents the formation of the crj^stals. Furthermore the lye for 
fig-g-ed soap requires to be still less caustic than that for the 
“Crown” soaps, as the soap must possess, even when cold, the 
necessary mobility to permit the crystals of potassium stearate 
to form. The more tallow or other solid fat is used, the thicker 
will be the soap, and the more carbonate must consequently be 
in the lye. If the lye is too caustic, the soap will remain per¬ 
fectly liomog-eneous in storing-, instead of crystallizing-. On the 
other hand, if it contains too much carbonate it crystallizes very 
readily, but also becomes syrup-like on storing-. 

The lye is made as described before for other soft soaps, or 
the lime is slacked in weak lye that may be on hand, and the 
potash dissolved in the latter. About 40 to 42 lbs. of lime are 
required for 100 lbs. of pearl ash; a little more in summer. 

The stock may be: Linseed oil or cotton seed oil, 65 parts; 
tallow, 35 parts; or, tallow, 40 parts, linseed oil, 40 parts, and 
cotton seed oil, 20 parts; or any similar combination. For yellow 
soap some palm oil may be added. The stock should be fresh, 
if possible; old rancid tallow requires to be previously purified. 
A greater proportion of tallow than just named causes smaller, 
but more abundant crystals. 

The stock is saponified as discribed for the ordinary soft 
soaps, and boiling- must not be carried too far, as an excessive 
evaporation of water retards, if it does not entirely prevent the 
crystallization, besides reducing- the yield. The sig-ns for a fin¬ 
ished soap are similar, as already described under “Crown Soaps.” 
When it sinks in the kettle while boiling-, and on shutting- off 
steam, only a small speck of froth is seen in the center of the sur¬ 
face, it contains the proper proportion of water. The soap may 
be known to have the rig-ht alkaline streng-th when a sample, al¬ 
most as soon as it is set on gdass, has a slig-htly turbid surface. 
The cold sample must be clear, with this sligdit turbidity barely 
perceptible; but after a short time it should no long-er be brig-ht, 


4 


247 


Soft Soap. 

but rather appear covered with a bloom such as is often seen on 
ripe fruit. 

When cooled in the kettle to 150° F., the soap is run into 
dry and clean barrels, which are stored in a cellar, at a temper¬ 
ature between 55° and 65 F., which is most favorable for crys¬ 
tallization. Other things being equal, this process will take less 
time as the proportion of tallow used is larger. 

For filling figged soaps silicate of potash is best adapted, as Fillin £* 
soda prevents in a measure the proper crystallization. The fill¬ 
ing may be added in the following manner: Mix silicate of pot¬ 
ash in warm water till the solution shows 11^° B. while warm; 
then add 38-40° potash solution to bring the strength up to 13^° 

B. warm. Into 435 lbs. of this solution crutch 300 lbs. of flour. En¬ 
ough of the soap is then added to form a tough mass, which must 
draw long threads on removing a small portion. This mass is then 
crutched into the soap in the kettle, when some caustic lye of 
27° B. must be added to restore the proper strength and consist¬ 
ency. The proportions used are about as follows: 

2,350 lbs. soap. 

300 lbs. flour. 

435 lbs. silicate solution. 

535 lbs. lye, 27° B. 

The soap to be filled should not contain too much carbonate, 
as the filling will shorten it to some extent. In winter less sili¬ 
cate and more carbonate is preferable. 

The carbonate, sulphate, or chloride of potash, especially 
the latter, can be used here also, as already described in the be¬ 
ginning of this chapter. Soda salts are unsuitable for figged 
soaps. 

ARTIFICIALLY FIGGED SOAP. 

The crystals of potassium sterate being produced by the use 
of tallow or similar fats, which are comparatively cheap in this 
country, there is scarcely any need of causing the same appear¬ 
ance by artificial means, as is a very common practice in coun¬ 
tries where tallow is very high in price compared to other stock. 

But in highly filled soaps also the crystals are often represented 
artifically. This is done—to the detriment of the quality of the 
soap, of course—by breaking well-burned lime into very small 
pieces, and sifting those out which pass easily through a coarse 
-ieve, but do not go through a sieve of say sixteen meshes to an 


248 


Soft. Soap. 


inch; these small pieces of lime are crutched into the hot soap 
and swell up in the same by absorbing* water, making* a very 
close imitation of the naturally fig*g*ed soap. Chalk is some¬ 
times similarly used, but is less satisfactory, and artificial grains 
of various kinds are even an article of commerce. 


CHAPTER XI. 


General Remarks on Boiling Soaps. 


The chapters VII., VIII and IX. have been devoted to a 
description of the methods employed in this country for boiling 
the hard soaps used in the laundry and for g-eneral household 
purposes; the operations of perfuming-, pressing- and reworking 
of scraps will be described in separate chapters, as will also the 
boiling- of toilet soap for milling. 

«1/ kL* 'll- vlx -V- 

'T' *T V 'T' «T* vv 

A special variety of marbled soap, which also contains a Artificial n 
large proportion of water, may be made by cooling a boiled soap 
just enough to bring it to the consistency required to keep the 
coloring matter suspended. When the coloring matters are then 
crutched in, the marble is formed in a manner similar to that 
observed in soap thickened by boiling down. 

* * * * * * * 

There have been invented numerous devices and methods TT 

^ anous 

with a view to improve the ordinary boiling process, such as boil- cesses, 
ing the fats under strong pressure with carbonated alkali, boiling 
with superheated steam, etc. It is very unlikely, however, that 
a great change will ever be generally adopted from the present 
ordinary boiling process, for, as said before, it is difficult to im¬ 
agine anything more simple. The only direction in which real 
improvements are to be looked for is in the mechanical appli¬ 
ances used for the various requirements of the soap factory, and 
possibly in the employment of new raw materials. 

* * * * * * * 

The manipulations described in the preceding chapters, if simpiiiie 

A C6SS6.S, 

properly carried out, will furnish excellent products in each case. 


avble 


p r o 


(1 pro 




\\ aste Lye 


i 


250 General Remarks on Boiling Soaps. 

It is true that not all soaps are boiled as carefully and with as 
many “changes” as here described, but the simplified processes 
never give as good results. Nor will it be necessar}^ to describe 
in detail the various short cuts by which two or more operations 
are sometimes condensed into one, for there is nothing- mysterious 
about the boiling- of soap, and whoever desires to do so can 
readily determine how to abbreviate the making- of any soap by 
carefully considering- the reasons stated why each operation is 
conducted just as it is. For instance, a careful perusal of the 
chapter on Settled Rosin Soap will sug-g-est that such a soap 
could be made by saponifying- the tallow and rosin in one oper¬ 
ation, thereby saving- one chang-e; then an excess of strong- lye 
could be used instead of salt (or brine) for .graining- the soap, 
thereby saving the strengthening change also; the soap could 
then be thinned for settling directly after running off the lye 
used to grain the soap. 

Or, if this is not simple enough yet, the tallow and rosin 
could be saponified with just enough lye to leave the soap very 
nearly neutral, and then the latter could be thinned directly for 
settling. 

These and other suggestions will readily occur to the prac¬ 
tical soap maker, who will also understand their disadvantages. 
For this reason they have not been treated at length in these 
pages. 

We repeat, there is no mystery about the boiling of soap, but 
an intelligent understanding of all the raw materials, fats, lyes, 
salts, and of the “reasons why” of all the different operations is 
required, in order to come to correct conclusions in determining 
the course to pursue in given cases. For this reason these pages 
have been devoted to explanations rather than to hard and fast, 
but unexplained formulas, which the uninitiated could no more follow 
than the average human being could steer a ship across the oce¬ 
an, had he ever so high priced maps to guide him. 

****** * 

Formerly much speculation was indulged in as to the best 
method of “regenerating” partly spent lyes, so as to bring them 
into proper condition for using them over again. At present they 
are either worked up for glycerin, if from the first change, or 
their remaining strength is utilized by boiling with fats and fat¬ 
ty acids, to recover the strength of the carbonate as well as the 
caustic soda. 


General Remarks on Boiling Soaps. 


251 


The weight of soap yielded by a given amount of a certain Yield 
fat or rosin is a matter of practical importance; but owing to the 
various kinds and qualities of materials used a positive answer 
that will hold in all cases cannot be given to this problem. One 
lot ot tallow or other fats, or of rosin, will turn out differently 
than others; besides the proportion of water present in the fin¬ 
ished product is not always the same. (A moderate amount of 
water must be present in every hard soap, besides the fatty acid 
and alkali, and is therefore included in the yield. Filling of 
any kind is, of course, not included in speaking of the yield of 
actual soap). The increase consists of alkali and a moderate 
proportion of water—less the glycerin lost—and of course is 
somewhat higher in settled soap than in the boiled down soap. 
There is also considerable difficulty in ascertaining the exact 
yield in a given case, from the fact that in a large boil on a man¬ 
ufacturing scale it is next to impossible to accurately weigh all 
the fat and rosin used, the good soap obtained less the filling 
that has been added before framing, and the good soap still con¬ 
tained in the nigre. 

It is therefore generally considered sufficient to estimate 
that “100 lbs. tallow, saponified with soda lye yield about 150 
lbs. of soap; rosin increases slightly less than tallow; cocoanut 
oil yields somewhat more.” 

An experiment on a small scale would permit of more accu¬ 
rate observation, but it is impossible to say just how near the re¬ 
sults are to those actually obtained in the factory. The details 
of such an experimental boil recently made by Mr. C. Melzer, 
and reported by him to the American Soap Journal , are of interest 
in this connection; the following is an extract of the essential 
parts of the same: 

“The quantities operated with were 10 pounds 74 per cent 
Solvay caustic soda, 25 pounds prime tallow, and 25 pounds K 
rosin. The 10 pounds caustic soda made 67 pounds lye of 20 B. at 
60° Fahr. To saponify the 25 pounds tallow I required 26 pounds 
of the 20° lye and produced 42)4 pounds curd soap. The waste 
lye which was very slightly alkaline marking 12 B. at60° Fahr 
Without removing this waste lye I added to this soap in kettle 
the 25 pounds K rosin, used 23pounds of the 20 lye for 
saponifying the same, and grained out with a little more salt. 

The total soap now weighed 81 yi pounds, showing that the 25 
pounds rosin had produced 39 pounds. The very dark-colored 


of hard 


252 


General Remarks on Boiling Soaps. 


waste lye now marked 14 B. at 60° Fahr. and contained alkaline 
strength which I estimated equal to 1 or 1)4 pounds of 20° lye, 
thus leaving* 22 or 22)4 pounds 20 lye actually required for 
saponifying- the 25 pounds rosin. 

“The appearance and general properties of this 100 per cent, 
rosin-soap correspond to the old-fashioned boiled-down rosin 
soap of anti-bellum times of which it was said that it answered 
equally well for washing the clothes and for rosining the bow. 
Next, I settled this soap in the usual way, and after a repose of 
four hours dipped out 49 pounds settled soap. There were pro¬ 
bably two or three pounds more, but this could not be dipped 
out without getting more or less nigre also. This settled soap 
is of good color and filled with 7 per cent. 33° Carb. soda solu¬ 
tion (i lb. 58 per cent Solvay Process Co. “Pure Alkali” (Carb. 
Soda) make 3 >2 lbs. solution of 33 at 120° Fahr.) looks all right, 
but, of course, is quite sticky. Adding salt brine to the nigre I 
boiled it down to a sharp grain which weighed 34)4 lbs. The 
waste lye weighing 15 B. at 60° Fahr. remaining clear and had 
very little alkaline strength. Of course this weight of settled 
soap and nigre is disproportionate, the settling operation on so 
small a scale being imperfect. In practice the nigre is much 
smaller, varying from one-fifth to one-third of the total. It will 
be noticed that the combined weight of settled soap and nigre 
is two pounds greater than that of the curd soap previous to settl¬ 
ing, which difference represents the extra water held in the settl¬ 
ed soap. 

“Why we should be able in an experiment like this to pro¬ 
duce a larger quantity of soap with a smaller quantity of soda 
than in actual practice I cannot explain, unless it is that in the 
experiment we know the quality and quantity of the materials 
and of the product, whilst in actual practice we do not. In the 
experiment referred to, I used at the rate of lbs. 74 per 

cent caustic soda to saponify 100 lbs. of stock consisting of equal 
parts tallow and rosin; in actual practice the proportion of rosin 
as compared to the fats is about 50 rosin to 100 fats, and if these 
figures are taken as a basis, it will be found that I used )ust 
about 15 lbs. 74 per cent caustic soda to the 100 lbs. of stock. 
According to the law of equivalents this is more than enough; and 
whilst I do not wish to prove my figures in this way, I shall hold 
that they are about correct until convinced of the contrary by other 
means than the results supposed to be obtained in actual practice.” 


General Remarks on Boiling Soaps. 


253 


Referring- to calculating- the yield in actual practice the same 
writer remarks: 

“The manufacture of commercial soap is not an exact sci¬ 
ence; we may say that the acids and bases employed in soap mak¬ 
ing- will only combine in fixed proportions according- to their 
equivalents, and any surplus of one or the other will not enter 
into the combination no matter what the soap maker may do. 
That is all g-ood enoug-h, but the practical soap maker does not 
aim to produce a neutral salt, that is, not g-enerally. To attempt 
to tell, from accounts kept in the factory, in any but an approxi¬ 
mate way, how much of this and that material was used, and how 
much soap was produced therefrom, is impossible. I keep ac¬ 
counts of every batch of soap made in our factory, but make no 
pretense to their correctness other than that they show the pro¬ 
bable quantity of fats and rosin consumed and the number of 
frames of soap produced. 

“I will here quote from my kettle book the debits and credits 
of six successive batches of soap, which will show about as cor¬ 
rect results as is possible to obtain in this way. 

“The first two of these six batches of soap were made in 
clean kettles (kettles Nos. 2 and 3); on the nigres remaining 
therefrom two more batches of the same (high grade) soap were 
made, then the nigre in No. 3 was pumped into the nigre in No. 
2, and some stock added, and this made into a batch of second 
grade soap; after this the nigre in No. 2 was pumped into a nigre 
in kettle No. 1 remaining from a previous batch of low grade 
soap, stock added and worked again into a batch of low grade 
soap. The nigre now remaining in kettle No. 1 may be con¬ 
sidered an offset to the nigre previously in this kettle, and as I 
work up no soap trimmings in our kettles there is nothing to 
estimate in this direction. 

“The aggregate quantity of fats (tallow, white and yellow 
grease) used for these six batches, was 130,500 pounds, rosin 
44,500 pounds; soap produced, 292 frames. Our frames are 48 x 
42x15 inches and considered to hold 1,100 pounds of soap. I have 
never weighed one, and it is not convenient to do so, but taking 
the average of the quantity of soap we cut out of a frame, and add¬ 
ing to this the weight of the trimmings, 1,075 lbs. appears to be 
about right, and I take this weight as the basis: 292 frames of 
1.075 lbs. = 313,900 lbs. of soap, and deducting from this 36,- 
500 lbs. of carbonate soda, etc., added in the crutcher (the et 


254 


General Remarks on Boiling Soaps. 


cetera represents the perfume), we have 277,400 lbs. soap pro¬ 
duced from 175,000 lbs. stock consisting- of fat and rosin in the 
proportion of 100 fat to 34 rosin, or an increase of 58^2%. 
This does not show up so well as in the experiment, and in look¬ 
ing- for the probable cause, I find the following-, which in a 
measure applies to our factory only, but corresponding- causes 
may and probably do exist in every other factory. In the first 
place, our fats are pumped into the kettles from reservoirs sup¬ 
plied with a g-aug-e similar to those on railroad watering- tanks, 
each divisonon this g-aug-e representing- 1,000 lbs. of fat. Tak¬ 
ing- for granted that these gaug-es are correct with the fat at a 
certain temperature, say 110 Fahr., then the fats would always 
have to be measured when at this temperature or the necessary 
correction made if taken at a different temperature. This is not 
the insignificant matter it seems to be, for fats and oils are ex¬ 
panded more by heat than liquids in general, and based upon the 
figures given by Deite (Handbuch der Seifenfabrikation, page 
11) the difference in the volume of 25,000 lbs. fats or oils differ¬ 
ing 36° Fahr. in temperature, would be equal to about 500 lbs. 
This correction, however, is never made. A still more important 
item is the impurities and water held in suspension by the fats. 

“Several months ago, I worked up a lot of grease stearin 
which contained a very considerable amount of albuminous mat¬ 
ter, but this could not be readily separated, except from the 
spent lye of the soap, and ver} T recently we bought white grease 
that looked wet, but precipitated no water on being melted; a 
moisture determination, however, showed that it contains over 
19%. This grease is of peculiar nature and origin, but as it is 
not likely that the readers of the Journal will have any of it to 
deal with, I will not mention it further. With rosin it is even 
worse; there is opaque rosin and trashy rosin, and rosin of which 
we do not know whether it will increase 30 or 60%; it is even 
difficult to get at the exact weight. We weigh or average the 
barrels and deduct 40 lbs. for Alabama or 70 lbs. for Savannah 
cooperage, and when we come to a dark or trashy barrel, the whole, 
or such part as is bad, is thrown out and the estimated quantity 
deducted, or it is not. This may look like great carelessness to 
the theorist, but he would very probably do the same way if he 
were engaged in the manufacture of commercial soap on a reason¬ 
ably large scale.” 

The exact quantity of alkali required for saponifying a given 


General Remarks on Boiling Soaps. 


255 


amount of fat is a question which is of greater importance in 
making- soap by the cold or half-boiled process than in boiling-. 
During- the latter the soap-maker can determine when more lye 
is required, and can also readily see when an excess is present 
and remove the same from the mass; be is, therefore, content to 
use as much alkali as the fat can possibly absorb, as this increases 
his yield of soap. The quality of the stock is too variable to 
calculate with sufficient accuracy in advance the amount of alkali 
a large boil will absorb. In the cold and half-boiled process, 
however, the calculation is made as near as possible, since in 
this case there is no other way than to mix the lye with the fat 
in proportions estimated to be correct. 

* * * * * * * 

The temperature at which a soap is framed is of importance 
in most cases. Apart from the filling operations in the crutcher, 
as described under “settled soap,” the temperature also affects 
the behavior of the soap in the frames. A pure (unfilled) soap, 
cooling slowly in the kettle, will assume a different formation 
and texture than one poured hot into the frames (where it cools 
more rapidly than it would in the kettle), because in the two 
cases the crystallization of the stearin soap from the olein soap 
will proceed differently. This difference is noticed even between 
large and small frames. A soap which in a 3,000lbs. frame, for 
instance, shows a small crystalline formation and dries in straight 
lines after cutting, will have a large grain if run into a 6,000 Ids. 
frame, and will perhaps dry crooked after being cut into bars. 
This is a subject which must be studied in regard to each special 
soap made. 

******* 

From careful observation it appears that, just as soap is de¬ 
composed in the act of washing in ordinary water, so a certain 
amount of decomposition takes place each time a soap is “salted 
out;” at the same time the amount of free alkali present is re¬ 
duced. Thus a soap which, after salting out for the first time 
contained 0.30% free alkali and 0.56% free fatty acids, after a 
second salting out showed 0.19% free alkali and 2.25% free fatty 
acids, and another repetition of the process increased the free 
fatty acids to nearly 4%. 


Framing. 


Decomposition by 
graining. 



























































* 












* 
























" |; m H 

■Hi 























. 

















































? 


































































































. 











CHAPTER XII. 


Half=Boiled Soaps.* 


Gknerai. Remarks. 

The manufacture of soap by half-boiling- consists, briefly, Methods of hair 
in mixing the melted stock with lye, either (preferably) in the bomng ‘ 
crutcher or in the soap frame. The lye is used quite strong 
(say 35° B.) and the temperature of the stock may be taken at 
about 140° F. from the start, so that it will rise to 180-200° 
when the reaction of the lye on the stock causes the spontane¬ 
ous generation of additional heat. Others use the fat just 
warm enough at first to melt it, mix it with the lye, and when 
the ingredients begin to combine turn on steam in the jacket of 
the crutcher to raise the temperature to say 180 c F. or over 
(according to the stock, etc.), keeping it at about that point till 
the soap is of uniform consistency. This latter process has the 
disadvantage that it may easily cause the soap to boil over un¬ 
less carefully watched, and that a jacket crutcher or a water 
bath must be used, while the proceeding first mentioned permits 
of the use of an ordinary crutcher and, as already stated, may 


*The term “lialf-boiled” soap is not applied by all soap makers to 
signify the same thing. Mostly it is employed to designate those soaps 
which are made without actually boiling the ingredients, but are formed 
at a higher temperature than that used for the “cold-made ” soaps to be 
described in the next chapter. We shall employ the term in this sense in 
this treatise. (Others include in the denomination “half-boiled ” all hard 
soa p_other than cold—made without change of lye, and which therefore 
contain all the glycerin and impurities of the stock. This definition 
would therefore include the “ Escliweg ” soap already described in Chap¬ 
ter IX.) 





258 


« 


Half-Boiled Soaps. 


Advantages and 
disadvantages of 
half boiling. 


Purity of stock. 


Lye. 


Prepared silicate. 


• • 

even be carried out in the soap frame. In case stock containing' 
much free fatty acid is employed, the reaction is so rapid that 
much heat is quickly evolved, so that in such case the stock 
should be used at a somewhat lower temperature; it is preferable, 
however, to remove the free fatty acids beforehand by preparing 
the stock as for cold-made soap. 

It will be readily understood that the action of the lye on 
the stock is necessarily less complete in this case than in the 
process of making- soap by boiling-, and that the product will 
naturally contain some uncombined ingredients, besides all the 
impurities that may have been present in the stock and lye, and 
the glycerin formed by the chemical action. But, on the other 
hand, this process permits of remedying defects which may ap¬ 
pear in the course of manufacture, which is not the case in the 
cold process, to which it is therefore superior. The soap will 
also be somewhat imperfect on account of the impossibility of 
calculating exactly the amount of lye to be used for a given am¬ 
ount of stock; however, the half-boiling process is in this res¬ 
pect preferable to the cold process, since it is possible to make 
necessary corrections when making soap by half-boiling, if to¬ 
wards the finish there is either a lack or an excess of strength 
apparent. 

The purification of the stock being of special importance, 
the treatment with lye as described for bleaching tallow (page 
43) is applicable for all kinds of stock for this purpose; or any of 
the other bleaching processes mentioned in the description of 
various fats and oils might be used, if preferred. The lye treat¬ 
ment is indicated, also, for the removal of free fatty acids from 
the stock, as the presence of these interferes with the proper 
saponification in all cases where actual boiling is not employed. 
In the process of bleaching those impurities are removed whose 
presence is especially objectionable as tending to impair the 
keeping property of the soap. 

The lye used for half-boiled soap should be as caustic as 
possible; in other words, should be made from the highest grade 
of caustic, as the presence of foreign salts in the lye is an ob¬ 
stacle to the proper combination of fat and lye. (Compare also 
the remarks on this subject under “Cold-Made Soaps.”) 

If silicate is used in the soap, care must be taken that the 
same has sufficient alkaline strength. Ordinarily to every 100 
lbs. silicate 25-30 lbs. of 35° lye must be added, in order to pre- 


Half-Boii.ed Soaps. 


259 


vent the silicate from crystallizing - in the soap, from lack of 
strength. To properly prepare the silicate for this purpose the 
lye is added until its presence is perceptible to the taste, then 
just enough silicate is added till the taste of the lye disappears 
ag’ain; prepared in this manner the silicate will not spoil the 
appearance of the finished soap by crystallizing - or coming - to 
the surface; nor is it so likely to cause soft and spongy parts in 
the middle of the frame, as unprepared silicate is very apt to do. 
If preferred the silicate may be mixed at the start with the lye 
required for a batch of soap, and sufficient of that lye be used 

for both fat and silicate. 

# 

The soap being g-enerallyof a very dense consistency, owing 
to the low temperature employed, the crutcher should be ar¬ 
ranged to run slowly when used for the half-boiling process, 
and stirring should be continued only as long as necessary; to 
attain this object it is desirable to have the crutcher connected 
with a separate engine, whose speed can at all times be adapted 
to the requirements of the crutcher Or, where this is not pos¬ 
sible, the cog-wheels on the crutcher (or the pulleys on the 
counter shaft) must be arranged so as to give a slow speed to 
the machine. When half-boiled soap is crutched fast or too 
long it is apt to become spongy and floating by the incorpora¬ 
tion of air bubbles. 

For the same reason those crutchers which have a screw 
and center tube (see Fig. 33-41) should be filled sufficiently to 
have the latter covered at least with two or three inches of soap, 
so that in falling over the edge of the center tube the contents 
cannot catch air. The size of the frames should correspond with 
the capacity of the crutching machine, when the latter is filled 
as indicated; or if the frames are not large enough the center 
tube of the crutcher will have to be cut down sufficiently. The 
crutcher should always be heated somewhat before running in 
any of the stock, as this not only guards against undue cooling 
off, but also prevents the soap from sticking to the sides and 
causing lumps in the mass. It is also a convenient arrangement 
to connect the steam pipe which leads to the jacket with a cold 
water pipe, to be used in case the oil should be too hot at any 
time. This cold water connection is also very useful because, 
by applying cold water in the jacket in time, as soon as signs of 
rising are noticed, boiling over may be prevented which is other¬ 
wise very liable to occur at times. (See Fig. 23). 


Crutching. 


260 


Half-Boiled Soaps. 


Amount o 
used. 


Pearl a s 
tion. 


Strength o 


i iye Particular attention must be paid to using - the correct am¬ 
ount of lye required to saponify the stock for a batch of half- 
boiled soap. An excess of lye will make the soap too sharp; if 
not enough lye is used part of the fat remains unsaponified, the 
soap will be smeary and soft and, if the miscalculation is con¬ 
siderable, the soap in the crutcher will be so thick that it is al¬ 
most impossible to get it out for framing. As to the proper 
amount to be used, variations occur, owing to the differences in 
the stock, to the grade of caustic, and to the purpose for which 
the soap is to be used, washing soaps made by half-boiling or by 
the cold process being frequently made intentionally so as to have 
a very slight excess of strength. (See also the remarks on this 
subject in the chapter on cold-made soaps.) 

In calculating the amount of lye necessary, the figures 
named in the chapter on the cold process may be used as a basis; 
but it must be remembered that a more perfect combination re¬ 
sults from half-boiling, for which reason from 2 to 3 per cent more 
lye may be used in it than for the cold process. Of a very pure lye, 
and for average stock, about 335 lbs. of 35^ B. soda lye may be 
calculated for 600 lbs. of tallow and similar fat; only for cocoa- 
nut oil about 355 lbs. are required. As said before, if this am¬ 
ount is found to leave the soap either too week or too sharp, it 
is an easy matter to make the necessary correction in the 
crutcher before framing. 

1 soiu- Strong pearl ash solution is sometimes added to the mass in 
the crutcher from the start, as it renders the soap more liquid 
and better to work; it also improves the texture of the product 
by giving it a finer grain, but as it does not combine with fats 
the finished soap will contain free carbonated alkali. To avoid 
this in a soap intended for toilet purposes, it is more to be 
recommended that some of the caustic soda lye be substituted by 
caustic potash lye, instead of using the pearl ash solution. 

ive. Regarding the proper strength of the lye for half-boiled 

soap, 35° is in most cases best adapted. Tallow, cotton seed oil 
and olive oil, however, if worked with only a small addition of 
cocoanut oil, make a smoother soap when the lye is reduced to 
30-33 B. As it is a great convenience in some cases to know 
about how much water is required to reduce a certain amount of 
lye of a given strength to one of the weaker degree, we give 
the following example of such a calculation, which will answer 
in cases where the lye is to be diluted only by a few degrees : 


Haef-Boieed Soaps. 


261 


Supposing- our lye is 39°, and we want to use 350 lbs. lye at 
35°; how much lye and how much water must we take ? Ans¬ 
wer : 350x 35-12,250 lbs.°; divided by the degrees of our lye: 
39 -j- 12,250 = 314. There are therefore required 314 lbs. of 39° 
lye and the balance (36 lbs.) of water. This calculation is not 
absolutely correct, but sufficiently so for most purposes when 
the lye is to be diluted only by a few degrees. 

If the soap made is to be white, a trace of ultramarine blue 
is frequently added, whereby the naturally yellow tint is changed 
into a less noticeable greenish color. The addition of some pot¬ 
ash or sal soda solution will also make the soap appear whiter, 
but at the same time make it more brittle and alkaline. If 
starch, silex or any similar fillers are to be used, they are mixed 
with the oil before running it into the crutcher and the mixture 
strained into the latter to avoid lumps. If, in cases of extremely 
high filling, the oil cannot hold all this extra material without 
thickening too much, some of it must be added to the lye (ex¬ 
cept the starch, which would form a stiff paste and not work 
well). 

If many batches of soap are to be made, requiring many suc¬ 
cessive weighings of fats and lye, it is best to have two scales, 
with a sheet iron pan each, provided with a faucet near the bot¬ 
tom to empty it. The fat is run into one of the pans, weighed, 
and the faucet opened to let the stock run into the crutcher ; the 
lye is then similarly weighed, etc., on the other scale. When 
only one scale and one pan are used the weight of the latter is 
increased with every weighing, owing to the remnants of fat and 
lye, which will partly saponify and remain behind on emptying 
the pan, thus giving rise to errors in weighing. The particles 
of soap are also liable to stop up the faucet. 

The process of making soap by half-boiling resembling the 
cold process in many particulars, some further useful hints may 
be found in the chapter describing the latter, to which the reader 
is referred. 


Diluting lye. 


White soap. 


Filling. 


Weighing the 
stock. 


Similarity to the 
cold process. 


HALF-BOILED WHITE SOAP. 

To make a white soap by half-boiling, proceed as follows, 
observing at the same time the preceding “General Remarks”: 

The fat may consist of any suitable combination, such as, 
tallow 4 parts, cocoanut oil 1 part, cotton seed oil 1 to 3 parts, 
clarified in the manner referred to before. The amount of lye is 


262 


Half-Boiled Soaps. 


Using weak lye 
for correction. 


Crutcliing after 
framing. 


calculated with reference to the nature of the stock used, in ac¬ 
cordance with the figures just given. If silicate is to be added 
also, it must be prepared with lye, as already stated. The fats 
are used at a temperature of 140° F., and the lye at the ordinary 
temperature of the atmosphere in summer; in cold weather the 
lye should be brought to a luke warm temperature. The silicate 
is first crutched in, and then the lye. (Or, if preferred, the sili¬ 
cate may be previously mixed with lye, as already explained.) The 
mixture is now allowed to stand for 1 to 1)4 hours, until it is ob¬ 
served to become heated by the action of the lye on the fat. Then 
the crutching machine is started slowly , and if the soap shows 
(by its taste) a deficient alkaline strength, a few pounds of lye, 
diluted to 10° B., are added, so that the desired strength is at¬ 
tained. Strong lye should not be used for this purpose, as it 
would cause the formation of lumps. If, on the other hand, the 
soap is observed to be too strong, a little cocoanut oil must be 
added. These additions, however, must never be made until the 
mass has been standing in the crutcher at least 10 to 15 minutes 
after the the machine was started up. Different stock does not 
combine with the same rapidity, which must also be taken into 
consideration. 

When the materials have combined into a homogeneous mass, 
the soap is run into the frame and stirred by hand for 15 to 20 
minutes, in order to avoid the formation of streaks. This is a 
rule which applies to all smooth soaps made by half-boiling. 

A somewhat different soap results from the following slightly 
changed proceeding and different stock : 


Tallow.440 lbs. 

Cocoanut Oil. 60 lbs. 

Soda Lye, 34° B.220 lbs. 

Potash Lye, 30" B. 60 lbs. 


The fat is heated to 125 F. and the lye worked in; the 
crutcher is covered, and in 1 to 1)4 hours the mass will become 
heated by the chemical union of the ingredients. If necessary to 
do so, steam is then very carefully turned on to bring the heat to 
about 180 F. and retain it at that point for some time, until the 
soap is uniformly clear and well formed, when it is run into the 
frames. 

HALF-BOILED SOAP FOR MILLING. 

Although the soap for milling purposes is made in most 
cases by boiling, the half-boiling—and even the cold process— 






Half-Boiled Soaps. 


263 


are occasionally employed, although they are less to be recom¬ 
mended for this class of soaps than for any other. A soap of 
this kind may be made of about eight parts of tallow and two 
parts cocoanut oil, treated in the same manner as just described 
for a white soap. Another suitable combination is : 

350 lbs. tallow, 

200 “ cocoanut oil, 

50 “ castor oil, 

300 “ lye, 38° B., diluted with 
26 “ water. 

As milled soap, more than any other, is expected by the con¬ 
sumer to be well made and to retain its fine appearance and odor 
for a long time, it is necessary to observe every possible precau¬ 
tion to secure the most thorough saponication possible. If an 
appreciable proportion of unsaponified fat remains, the soap will 
soon turn rancid, acquire a dirty color and a rank odor. On the 
other hand, a milled soap is expected to be also free from uncom¬ 
bined alkali, and an excess of strength is, therefore, to be avoid¬ 
ed with the same degree of care. While it is not possible to 
manufacture a faultless piece of soap, except by careful boiling, 
a salable and for many consumers quite useful milled soap may 
be prepared by half-boiling. 

As a means to promote the combination, a solution of sugar 
in water is sometimes added to the soap, which thins it out some¬ 
what and helps to bring it into a condition favorable to more 
complete combination. 

The process of milling itself will be described in a separate 
chapter. 

HALF=BOILED flOTTLED SOAP. 

The manufacture of a mottled soap in the crutcher is not 
entirely satisfactory. However, as it may be profitable in some 
cases, we give herewith the points to be observed. The soap 
must be made neutral, and resembles in most particulars the 
Eschweg soap described in chapter IX., but, owing to the lower 
temperature, the tests there given for the proper finish are of no 
use in a half-boiled soap. 

The materials used may be as fallows: 

500 lbs. tallow, 

» 100 “ cocoanut oil, 

100 “ cotton seed oil, 

410 “ lye, 34 or 34^° B. 


264 


Half-Boiled Soaps. 


The stock to be of a temperature of 150° F. It is necessary 
to leave the soap, when it seems to be finished, in the crutcher 
for at least 15 to 20 minutes longer, as it might happen that the 
soap is deficient in lye; it would then become weak in the frame, 
although it may have appeared just right in the crutcher, unless 
lye is added as soon as it is observed that, on standing in the 
crutcher, all the strength has disappeared. 

After saponification a solution is added consisting of 8-10 lbs. 
salt and 6-8 lbs. potash in 50 lbs. of water, the desired color hav¬ 
ing been mixed in the brine. The frames must be well covered 
until the mottle forms. Silicate—prepared with lye—and other 
fillers may be used. (Compare also “Eschweger III.” page 229). 

HALF-BOILED FLOATING SOAP. 

This may be made of tallow (or grease) and a small propor¬ 
tion of cocoanut oil. The batch is made of such a size only that 
the center tube in the crutcher is above the surface of the soap 
so as to cause the soap falling over the rim to catch air in crutch- 
ing. The stock should be at about 120 F., and no steam is ad¬ 
mitted into the jacket after saponification has set in. After 
crutching briskly until a sample taken out is quite light, and 
swims on water when cold, the soap is framed and allowed to 
cool as quickly as possible, that it may retain the air bubbles 
evenly throughout the frame. If the soap is made too warm, it 
will settle in the frame and will not float after pressing. (Min¬ 
eral soap stock and some silicate might be used for filling, but 
are not to be recommended in this class of soaps). 

Soap made by half boiling, of stock containing x /z or more 
of cocoanut oil, is difficult to make so that it will not float, as its 
consistency is such that it will retain any air that may be crutched 
into the mass. 

In this soap particularly the lye should be as caustic as pos¬ 
sible, and care must be taken not to make the soap too thin. 

ROSIN SOAP BY HALF-BOILING. 

When a rosin soap is to be made by the half-boiling process 
the rosin is melted together with an equal amount of tallow, 
strained, and weighed in with the other stock. The temperature 
of the stock and lye must not be above 130° F., for rosin saponi¬ 
fies more quickly and causes greater heating in combining with 
the lye than does oil. With a higher temperature than 130° F. 


Half-Boiled Soaps. 


265 


on the start the soap is liable to become so hot that it would rise 
out of the crutcher, and the part not spilled would be spongy and 
floating. The soap thickens rapidly and must be framed with¬ 
out waste of time; in the frame it becomes heated spontaneously 
a second time and the previously rather doubtful looking mixture 
becomes a good soap. 

A friend in Marseilles kindly furnishes the following ex¬ 
ample of how this soap is made in France: 


Cocoanut oil,.2,000 lbs. 

Palm oil (Lagos, red). 200 “ 

Rosin. 600 “ 


About one-third of the required lye, made of 70-72° soda, is 
heated to 90 C. (194° F.) and then the entire stock is thrown in 
and the heat slightly increased. Now the remainder of the 
necessary lye is introduced in small portions till the soap indi¬ 
cates by becoming clear that it is well formed. The soap is fill¬ 
ed (shortened) by a solution of half soda ash and half pearl ash, 
and finished by boiling lightly for about half an hour, when it is 
covered until next day. The whole operation takes 5 or 6 hours. 
A rosin soap made by the half-boiling process will take all kinds 
of filling, the same and even better than a settled rosin soap, if 
made with lye of from 30-35 B., and will give from 157 to 165 
lbs. soap from 100 lbs. stock, without the filling. The addition 
of a little palm oil will improve the color. 

(See also formulas in chapter on the cold process). 

TAR SOAP BY HALF-BOILING. 

Weigh the stock into the crutcher, and use not over one- 
tenth to one-sixth tar, because a greater quantity would make 
the soap soft and color the lather. According as the stock is 
more or less hard, use the lye at 36 or 37 B. The stock may 
consist of say 250 lbs. cocoanut oil, 250 lbs. tallow, 50 to 100 lbs. 
tar, and 275 lbs. lye at 36° B. The materials will join in ^ to 1 
hour. The temperature at first should be as low as possible, and 
care must be taken not to use tar admixed with water, as isolten 
the case. After the materials have joined they should be left in 
the crutcher for 15 to 25 minutes, as the stock saponifies un¬ 
equally and the soap might prove sharp to the taste for some 
time; if stock were then added to take out this strength 
the soap might prove weak and too soft in the frame. If pre- 





266 


Half-Boiled Soaps. 


ferred, the soap may be made in the ordinary way and the tar 
crutched in when the soap has been well formed. 

FILLED HALF-BOILED SOAP. 

(Specially suitable for Laundry Chips.) 

315 lbs. tallow. 

55 lbs. cocoanut oil. 

40 lbs. mineral soap stock. 

185 lbs. silicate of soda. 

30 lbs. 32° B. potash solution. 

280 lbs. 35° lye. 

Warm the stock to 140 B. and add the lye as in the other 
soaps described. When the soap is in the frame, crutch it till it 
is quite thick. 

HALF-BOILED COCOANUT OIL SOAP. 

A pure cocoanut oil soap may be made by half boiling- in the 
manner described in the preceding- pag-es. As has been stated 
already on various occasions, this oil lends itself more than any 
other for filling- with various salt solutions, without causing- the 
soap to become soft, especially if an excess of lye be also used. 
Such soaps are of course not to be recommended, as they are 
wasteful in use and injurious to the skin; but since there is a 
market for soaps of this kind, at prices at which better products 
cannot be furnished, the manufacturer is often practically com¬ 
pelled to make them. 

We append the following- receipt as an example: 


Cocoanut oil. 300 lbs. 

Soda lye 34° B. 225 lbs. 

Potash. 60 lbs. 

Salt. 40 lbs. 

Soda ash. 20 lbs. 

Water. 385 lbs. 


The water is heated and a portion of it used to dissolve the 
potash and soda ash; the remainder is used to moisten the salt. 
About two-thirds of the lye are crutched into the oil, and when 
the ingredients combine some of the hot water is added. When 
the mass is uniform, the soda and potash solutions are added al¬ 
ternately, in small portions. The salt is next added, and then 
the remaining one-third of the lye. The temperature of the 
soap must, during the whole operation, be maintained at 190 to 








Half-Boiled Soaps. 


267 


195° F. When all is incorporated, the soap is covered up for two 
hours. At the end of this time, if there is any froth on the sur¬ 
face, a little more water is required. If small samples taken out 
are too hard or too sharp, a little oil mixed with some hot water 
is crutched in. 

The amount of filling- which such soaps will absorb, in the 
form of various salt solutions, is almost unlimited, but they natu¬ 
rally dry out considerably on aging-. 

The above process is highly recommended by some soap- 
makers of the old school, but it should be added that the soap 
will turn out fully as well made if a go > 1, pure soap is made 
first, and the filling added only when the soap proper has been 
finished. 


TRANSPARENT SOAPS. 

V 

These are made very largely by half-boiling, but will be de¬ 
scribed in a separate chapter. 



































































» 



















CHAPTER XIII. 


Cold=Made Soap. 


ADVANTAGES AND DISADVANTAGES OF THE COLD 

PROCESS. 

As was explained in Chapter VI., the “Cold Process” of 
making’ soap consists in intimately mixing with each other cer¬ 
tain proportions of the fats or oils and strong lye, at about the 
melting temperature of the stock, and then running the mixture 
into the frames to work out its transformation into soap by it¬ 
self, with the aid of the heat generated spontaneously by the ac¬ 
tion of the ingredients on each other. As the chemical action 
progresses, the mass rises in temperature, until at last the fat 
and lye have combined, when chemical action gradually becomes 
less energetic and at last ceases altogether; the heat disappears 
slowly, and at the same time the soap formed hardens in conse¬ 
quence of the lowering of the temperature. It is seen that no 
separation of waste lye takes place in this process, and cold-made 
soap, therefore, contains—like half-boiled soap—all the impuri¬ 
ties that may have been introduced with the stock, all the water 
used for making the lye, the foreign salts that may have been 
contained in the caustic, the glycerin formed during the forma¬ 
tion of the soap, and also more or less of the raw materials in an 
uncombined state. The cold process is applied chiefly to the 
manufacture of laundry soap and of the cheapest grades of toilet 
soap, and sometimes also to soft soap. As it resembles in many 
particulars the half-boiling process described in the preceding 
chapter the reader, is referred to the same for additional details. 

As may be readily supposed, a method of manufacturing 
soap, so different from the boiling process, has certain advant- 




270 


Cold-Made Soap. 


ages as well as disadvantages of its own, and according to vari¬ 
ous conditions and circumstances a factory may find it advanta¬ 
geous to make all "its soaps by boiling, or all without uoiling, or 
it may use both processes for different products. 

Many of the smaller factories which work by the cold process 
exclusively, undoubtedly did so in the first place because a com¬ 
paratively small outlay was sufficient to buy the necessary plant 
for making soap without boiling; and once having established 
their special brands, these factories generally find it neither con¬ 
venient nor advisable to change their products by adopting new 
manufacturing methods. A mixing vessel with suitable stirring 
apparatus, a lye tank, a few soap frames, a furnace for melting 
the stock, a press to finish the cakes, and a few smaller imple¬ 
ments,these constitute the machinery required with which alone, 
if necessary, a soap factory on the cold process can be, and fre¬ 
quently has been started. 

Another reason why the cold process exclusively is employed 
by some factories, is the fact that small quantities of soap can be 
very conveniently made by it. The boiling of soap requires ap¬ 
paratus, labor and time, which are too expensive to apply except 
for a fairly large batch, to say nothing of the practical impossi¬ 
bility of properly finishing a small batch of soap by boiling. In 
connection with this there is the further advantage that by the 
cold process a batch of soap can be turned out on very short no¬ 
tice, and certainly much more rapidly than by boiling. 

Again, while experience and good judgment are certainly 
required to make a good soap by the cold process, it is at the same 
time easier to acquire a certain knack of making a passable piece 
of soap in the cold way, than it is to learn the art of soap boiling; 
probably this fact has also had a tendency to make the cold pro¬ 
cess a favorite with many smaller factories that are being estab¬ 
lished from time to time in towns growing at some distance from 
the larger cities. 

But, as mentioned before, there are also numerous factories 
making large quantities of soap by boiling which nevertheless 
use the cold process for certain of their brands, showing that 
there are still other reasons for making cold-made soap besides 
those just mentioned, depending on the properties of the product 
itself. Among these a prominent one is the fact that cold-made 
soap, while fresh, has a better appearance than almost any boiled 
soap, which is owing partly to its amorphous texture that causes 


Cold-Made Soap. 


271 


the cakes to preserve their square outline form for a longer time, 
instead of warping, like cakes of boiled soap. Their color also, if 
carefully made, is generally more beautiful. In general appear¬ 
ance a fresh, cold-made soap resembles a milled soap more close¬ 
ly than do the boiled soaps (but owing to its amorphous texture 
it has not the peculiar mark on the ends of the cake which milled 
soaps, and to a less extent also most boiled soaps, acquire in 
pressing). On aging, however, cold-made soap sweats readily, 
dries up, and then has a much less beautiful appearance than a 
boiled soap of the same age will possess. The length of time 
during which a cold-made soap will preserve its fine appearance 
depends partly on the care used in manufacturing it, on the 
amount and kind of filling used, and on the nature of the stock, 
cocoanut oil soap being less changeable in this respect than that 
made of tallow, grease, etc. 

The most important disadvantage under which cold-made 
soap labors, is the impossibility of securing a perfect combina¬ 
tion of the fat and lye, so that no free fat and alkali will remain 
present. Apart from the impossibility of calculating the exact 
proportion of lye which a'given amount of fat will require in or¬ 
der to form a neutral soap, it is also beyond the power of the cold 
process to combine all the materials perfectly, even if the right 
proportions were used. There will consequently, under all cir¬ 
cumstances, remain some free fat and some free alkali in the soap, 
causing sharpness and sweating on one hand, and (later on) 
rancidity on the other. In this respect the half-boiled process 
gives better results, although not equabto those of boiling. 

A peculiarity of cold-made soap is that it washes away more 
rapidly than boiled soap made from the same stock; it conse¬ 
quently lathers more freely and may perhaps be appropriately 
compared in this respect to floating soaps. 

SELECTION OF THE STOCK. 

When the cold process was first employed for soap making 
the lyes were still universally made by causticizing carbonate of 
soda in the soap factory; the resulting lye was rich in carbonated 
soda and other salts which are incapable of combining chemi¬ 
cally with neutral fats, and as a consequence the lye and the 
stock would not combine with each other to form salable soap, 
unless a large proportion of cocoanut oil was used with it. It 
thus came to be accepted as a rule that cold-made soap could only 


272 


Cold-Made Soap. 


be made by using- at least from one-third to one-half cocoanut 
oil in the stock. At present, however, where hig-h grade lyes 
are as easily made as those of lower grade the cold process can 
be employed for all kinds of stock, even without any cocoanut oil 
at all if so desired. 

The selection of the fats most appropriate for a soap of certain 
characteristics is the same as for boiled soaps, with the difference 
only that, along- with the other considerations, a naturally some¬ 
what readier solubility of cold-made soaps must not be overlooked. 

For some cold-made toilet soaps cocoanut oil alone is used, 
and these readily produce an exceedingly abundant lather, ow¬ 
ing to the naturally great solubility of cocoanut oil soap; it there¬ 
fore washes away rapidly, and a delicate skin cannot bear its 
constant use, as such a soap acts too energetically, for the reason 
just given. 

Of the several varieties of cocoanut oil the Cochin oil is pre¬ 
ferred for the cold process, especially for making white soaps, as 
it is the whitest, usually the freshest, and produces a soap which 
has less of the peculiar odor characteristic of cocoanut oil soaps; 
it also gives the product a better appearance, both for white and 
colored soap. However, its quality varies considerably indiffer¬ 
ent shipments, as is also the case with Ceylon oil, which some¬ 
times contains so much free fatty acids that thesoap thickens up 
before all the lye can be stirred in. This difficulty is overcome 
by purifying the oil, as described further on, and also in the 
chapter on fats and oils. But in factories where any other use 
can be made of such stock it is better to employ only the freshest 
cocoanut oil for the cold process, although it should be clarified 
under all circumstances. 

Next to cocoanut oil in value for cold-made soap is tallow, 
which is used in the stock in all desired proportions. When no 
cocoanut oil at all is used, as is the case for making what is 
known as “Soap Chips” for laundry purposes, it is advisable to 
add some softer material to the tallow, such as grease, cotton 
seed oil, etc. In fact, the before-mentioned rule applies here as 
well, that it is always best to use several kinds of stock together, 
so as to take advantage of the good qualities of each, and to 
counterbalance the bad ones. In some cases the addition of a 
small proportion of castor oil is advisable, as it causes the pro¬ 
duct to possess greater transparency and an improved texture 
resembling that of milled soap, and greater durability of the 


Cold-Made Soap. 


273 


colors and perfumes. The presence of a small proportion of 
castor oil is also useful in working- up the scraps, as it facilitates 
the process of remelting-; or, if the scraps are utilized by milling-, 
the result of the presence of castor oil is an improved texture of 
the milled article. When first made, a soap containing castor 
oil is a little softened by it, but it soon hardens. 

A material sometimes worked up in this connection is the 
flower pomades used by the perfumers.. When most of their odor 
has been extracted, they may be made into a delicately perfumed 
soap by the cold process. But this stock deteriorates rapidly, 
owing to the influence of the alcohol used in extracting the odor, 
and is then very difficult to work by the cold process, owing to 
the free fatty acids present. 

For a special quality of toilet soap an addition may be made 
of wool fat (Adeps Lanae), which does not saponify nor become 
rancid and makes the soap more emollient. According to its 
influence on the lathering properties of the soap, in other words, 
according to the stock used, from 3 to 8 % may be added. The 
method of applying it is to simply melt it in the warm stock. 
Such soaps are in the nature of super-fatted soap, but do not be¬ 
come rancid on keeping. If heated excessively, wool fat (lano¬ 
lin or adeps lanae) darkens the soap. 

For further details concerning the selection of stock the 
reader is referred to the description of different fats and oils 
(Chapter II), and to the special chapter (VI) covering this 
subject. 

PURITY OF THE STOCK. 

After selecting the kinds of fats according to the well-known 
properties of the soap which they form with alkali, the purity of 
the same is of the greatest importance, much more so for making 
cold-made soap than when they are saponified by boiling. All 
impurities of the fat must, therefore, have been removed before 
adding the lye, so that the soap maker may know just what ma¬ 
terial he has to deal with, and in order that the soap itself may 
be pure. All fats may be purified before use, in the manner de- , 
scribed elsewhere, but if very old they should be excluded alto¬ 
gether in making soap by the cold process, as even purification 
fails to give good results in that case. 

As a preliminary step, melting the stock and resting it in a 
settling tank (as described under “Saponifying the Fat,” in 


274 


Cold-Made Soap. 


Settled Soap, Chapter VII), is to be highly recommended, also, 

• 

in the cold process, for the purpose of removing the coarser im¬ 
purities. The extent of the impurities removed thereby can 
hardly be realized unless the stock is weighed before as well as 
after settling. 

Besides the direct loss from very impure or adulterated stock, 
and the strongly alkaline soap apt to result from it, there is 
danger of a batch being spoiled altogether in case the fat con¬ 
tains such impurities as salt, water, sulphuric acid (from render¬ 
ing), etc., in appreciable quantities. 

No less important is the absence of free fatty acids from the 
stock. If old and unprepared fats are used in the cold process, 
the free acids combine very rapidly with the lye, and in doing 
so collect in lumps of partly formed soap, enclosing in their mass 
particles of fat which are thereby prevented from combining with 
the lye; as a result the product in such a case will be a poor soap, 
full of uncombined materials, quickly turning rancid, losing its 
perfume, and appearing smeary and yet sharp at the same time. 
In making soap under such conditions, the contents of the 
mixing vessel thicken up quickly, sometimes even before all the 
lye can be mixed in, and the resulting soap has a coarse texture, 
whereas a well-made, fine-grained soap results only when the 
mass is in a condition permitting it to be stirred or crutched for 
some length of time. Even if the consequences are not always 
so very noticeable, the soap made from fat containing free fatty 
acids will always be gritty and coarse-grained, and of generally 
inferior quality. 

In order to make uniformly good soap by the cold process, it 
is therefore always necessary not only to free the stock from all 
foreign impurities, but also from the free fatty acids, an opera¬ 
tion so much the more to be recommended as it also bleaches the 
stock at the same time, and thus causes a marked improvement 
in the color and clearness of the product, besides improving its 
quality as a detergent. 

The purification and bleaching of all kinds of stock for the 
cold process may be performed by treating the melted fat with a 
little strong lye and alum and agitating, as described on page 43 
for bleaching tallow. If preferred the following process maybe 
adopted instead: 

The stock after melting and settling orstraining, is run into 
any convenient vessel and brought to a temperature somewhat 


Cold-Made Soap. 


275 


below 180 F. For every 100 lbs. of stock 2 or 3 lbs. of 36° lye 
are then run in slowly and stirred in thoroughly for several min¬ 
utes. The lye will combine with the free fatty acids and the 
particles of soap forming will enclose and carry with them the 
other impurities of the stock. After stirring for a few minutes 
as stated, 2 or 3 lbs. of 22^ salt water are run in and stirred 
through. The vessel is then covered up (unless the atmosphere 
is very warm) and the contents are allowed to rest over night 
for the separation of the impurities. The stock should not be 
warmer than 180° F. because otherwise the impurities will re¬ 
main suspended in the oil. 

When, especially for laundry soap, it should be deemed un¬ 
necessary at any time to subject the stock to a special process, of 
purification, the temperature of the stock should be as low as 
possible when running in the lye; even if at first the soap shows 
signs of slightly congealing, the heat gradually liquefies it 
again and the soap may be finished without trouble. This pro¬ 
ceeding will produce a finer grain than when the stock is com- 
parativel} T warm. 

For cocoanut oil it is always advisable, however, to at least 
boil it up on strong salt water for half an hour, taking off the 
scum which rises until it comes up perfectly white. At this 
point the impurities are allowed to settle. 

QUALITY OF THE LYE. 

The quality of the lye that is used for making a soap by the 
cold process is of considerable consequence, and in fact as im¬ 
portant in a cold soap as in soft soap, Eschweg soap, or in any 
other soap that is made without a change of lye. It is in cold- 
made and in half-boiled soaps more than in any other that one 
can appreciate the force of the definition which explains that soap 
is “lye, diluted and modified by fatty matters.” But unlike the 
lyes used for Eschweg and soft soaps, that employed for the cold 
process is very simply determined: it is at all times to be made 
of the highest grade of caustic that can be obtained. 

76 to 77 % caustic, dissolved in soft water (preferably that 
condensed from the steam pipes, or rain water), protected from 
the atmosphere by an airtight covering, and allowed to rest till 
all impurities have settled out, makes the best possible lye for 
this purpose. Only when customers demand a very white look- 

r r J White soap. 

ing soap, can a lye of low-grade soda be used to advantage, to 


276 


Coed-Made Soap. 


which—for cocoanut oil soap—some salt may even be added. Soap 
made with such lye is really inferior in quality, but it is some¬ 
times demanded by customers who judge the product by the 
color. 

The lower grades of caustic contain impurities in the lorm 
of salts, especially carbonate of soda and common salt, which are 
not in any way affected by the fats, and, if the lye is made from 
such caustic, these salts remain unchanged as impurities in the 
soap, besides causing imperfect saponification by preventing the 
caustic alkali more or less from coming into that intimate con¬ 
tact with the particles of fat, which is necessary for there chemi¬ 
cal combination. A lye containing much carbonate of soda causes 
the soap made with it by the cold process to be soft and spongy, 
and under otherwise unfavorable circumstances may even losen 
the combination between alkali and fat to such an extent, that 
the fat will partly separate and collect in the centre of the soap 
frame, where the soap is the hottest. The same is true with sili¬ 
cate of soda (unless used in large quantity), and when a moder¬ 
ate proportion of the latter is used for filling, the soap will have 
to be run into small frames, so as not to retain too much heat. 
Besides causing the faulty saponification, the foreign salts have 
the disagreeable property—especially in winter—of coming to 
the surface of the soap with the water, on drying, and remaining 
behind as a dry, white crust when the water evaporates. This 
makes the soap unsightly, ruins the wrappers, and has a suspicious 
appearance to the mind of the consumer. 

To make the lye, the caustic should be dissolved, as said be¬ 
fore, in pure, soft water. If only hard water can be obtained it 
would be well at least to boil it and let it settle, as thereby a 
part of the lime compound held in solution by hard waters is pre¬ 
cipitated. Or the water may be softened by adding 2 or 3lbs. of 
caustic soda to 1,000 gallons of water, and letting it settle. A con¬ 
venient tank for this purpose is one that has a faucet at the bot¬ 
tom for drawing off the sediment, and another one a few inches 
from the bottom, for the clear water or lye. When made, the lye 
should be at a strength of about 35 B. when hot, which will 
bring it to 38—39° when cold. It can then be diluted further, if 
wanted, without becoming hot again. If the lye when first made 
is above 39 : —40 it will become hot again on diluting it, which 
is generally best to avoid, as warm lye makes less smooth soap. 

After the caustic has been dissolved, the lye should be ex- 



Cold-Made Soap. 


277 


eluded from the air, as the latter always contains carbonic acid, 
which the caustic alkali absorbs eagerly, thereby becoming part¬ 
ly carbonated, and consequently reduced in purity and strength 
in a similar way as if it had been made originally from low-grade 
caustic. A simple method of protecting the lye in this respect, 
by means of mineral soap stock, was mentioned in the description 
of the lye tank, on page 93. 

Where the facilities are such that this can be done, the lye 
should be made early enough to give it several days’ time to 
clarify by resting, and drawn off carefully from the settled im¬ 
purities. If an occasion should arise when it seems desirable to 
filter the lye, this may be done by the aid of glass wool, packed 
into a glass funnel. 

Some brands of caustic, especially the lower grades, occasion¬ 
ally furnish a lye of a yellowish tint. For white soaps such lye 
is not well adapted, as their color is extremely delicate. The 
color of such lye may be removed by boiling it with 30 lbs. quick 
lime to each drum of caustic, and letting settle. 

Formulas for cold soap are usually based on the highest 
grade (say 76%) of caustic; if for any reason a lower grade is 
employed, the corresponding amount of the lower grade required 
may be calculated by multiplying the amount of lye called for in 
pounds by 76 and dividing by the figure which represents the 
grade of caustic actually used. 

As in all soaps, the substitution of a part of the soda lye by 
potash lye causes a marked improvement in the product of the 
cold process, as it renders the product milder, better in texture, 
more readily lathering, and slightly more transparent at the 
edges. Care must, of course, be taken to get good potash. As 
more potash is required than soda to saponify a given amount of 
fat, 7 lbs. of potash lye are generally used in place of 5 lbs. of 
soda lye. 

QUANTITY AND STRENGTH OF LYE. 

The exact amount of alkali required for the saponification 
of a certain amount of fat has been a matter of considerable spe¬ 
culation and finespun scientific calculations, but all the latter 
have been able to do was to prove that for practical work no ab¬ 
solutely correct figures can be set down, as fats are too variable 
in their composition and purity. Figures that are correct for a 
certain weight of, say a given lot of tallow, are not necessarily 


278 


Cold-Made Soap. 


correct for the same weight of some other lot of tallow. Then 
again, so long as the cold process cannot insure the perfect com¬ 
bination of all the lye with all the fat, there would really not be 
much advantage even in knowing the figures representing the exact 
chemical equivalents, for what the soap maker muststrive for is to 
so gauge the proportions of lye and fat as to make a soap as near 
as possible in accordance with our conception of an ideal soap. 
If we must needs employ the cold process for our purpose, then 
the question is not what proportions would give the best result 
//they could be combined, but the question is : “What proportion 
actually does give the best total results?” 

Some manufacturers, knowing that a certain weight of lye 
will make a mild soap, deliberately use a slight excess in order 
to have a product for the laundry or for general housework that 
will wash quickly. For toilet soaps, of course, the case is some¬ 
what different, and the manufacturer must keep within narrower 
limits. Under the circumstances we can give only approximate 
figures which are known to give good results under careful mani¬ 
pulation, and state under what conditions, as to strength of lye, 
etc., the alkali is best employed. 

Cocoanut oil requires more alkali for neutralization than any 
other known fat, and for a toilet soap made by the cold process 
it is universally calculated to require just one-half of its own 
weight of soda lye, if the latter is of 38 B. strength and made 
of 76% caustic. If the caustic soda is of a lower grade than 76% 
then correspondingly more must be used (or the lye is made of 
about 40° B.) If it is desired to use a weaker lye the quantitv 
of 38° lye necessary may simply be diluted as much as desired. 
For tallow, grease, lard, etc., half their weight of soda lye at 
36° B. is generally accepted as the proper proportion, they all 
requiring about the same amount of alkali. 

For 50 lbs. cocoanut oil and 50 lbs. tallow there are, in a 
similar manner, calculated 50 lbs. of 37 lye of 76% caustic 
soda. 

It will be observed that these amounts are slightly below 
those named for the half-boiled process, which is owing to the 
fact that in the latter more can be used, as the combination is 
more complete. 

Too much lye makes the soap not only sharp, but also exces¬ 
sively rough, hard and brittle. Small batches of soap do not 
develop as much heat as larger ones; they therefore do not com- 


Cold-Made Soap. 


279 


bine as thoroughly, and are apt to be somewhat sharper than 
larger batches made of the same proportions of material. 

An unfilled soap, made of 600 lbs. stock and 300 lbs. of 38 
lye, will have about 25% of water ivy its composition; for 100 lbs. 
caustic and 200 lbs. water make 300 lbs. lye of about 38° B., and 
these, with 600 lbs. of stock, make 900 lbs. of soap. 

Regarding the strength of lye, cocoanut oil and cotton seed 
oil saponify most readily with that of 38°, but for the other fats 
it is best to reduce it to 36° B. If the lye used is too strong the 
saponification of the fat will be less thorough, and the soap will 
be hard and rough as if an excess of lye had been used. For white 
cocoanut oil soaps which are to preserve their color for some 
length of time it may be well to reduce the strength of the lye 
with water to 36°; the soap will be somewhat softer at first and 
is therefore hardened by the addition of a little extra lye. This 
proceeding insures a better saponification and consequently 
guards the soap against rancidity. To keep the extra water 
from drying out a small addition of chloride of potash solution 
at a strength of 15 B. is sometimes also made, or part of the lye 
used is made of caustic potash. 

In some formulas the strength of the lye is given, with di¬ 
rections to dilute it with a certain amount of water. This is 
done because it is more convenient, and at the same time more 
exact, to use a certain amout of lye of ordinary strength and dil¬ 
ute it afterward as required, than to dilute it to a certain degree, 
to be determined by the hydrometer; the greater convenience is 
obvious, and the greater exactness follows from the fact that a 
lye shows slightly different densities, according to whether it is 
measured just after diluting and stirring it, or after resting for 
some time. 

TEMPERATURE OF STOCK FOR MIXING. 

The fats must be melted, so as to be in condition to mix 
thoroughly with the lye, and for the sake of economy in time, 
labor, and fuel, the stock is preferabl} 5 ' used when it has cooled 
off enough after bleaching it. Cocoanut oil is therefore best 
melted and prepared at least a day previous to using it; or before, 
if the quantity is large, so as to give it time to settle and cool. 
Tallow settles more rapidly and is ready almost immediately 
after bleaching, except for its high temperature; with the other 
stock already cooled, if both tallow and cocoanut oil are used 


280 


Cold-Made Soap. 


after settling-, the averag-e temperature may be about rig-ht. If 
for any reason it cannot be arrang-ed to have the stock cool off 
naturally, it will be necessary to cool it by means of cold water, 
either by leading- the latter throug-h a coils placed in the settling- 
tank, or by circulating- cold water in the jacket of the vessel in 
which the soap is to be mixed. 

If the stock is to be melted just before using-, it may be ad¬ 
visable to melt the tallow first, as it requires the greater heat, 
and then to add the cocoanut oil which melts at a lower temper¬ 
ature and reduces that of the tallow so that the mixture is just 
about rig-ht. 

Cocoanut oil alone may be saponified to the best advantag-e 
when cooled to about 70-80 F.; a mixture of equal parts, tallow 
and cocoanut oil, at 100-110 F.; tallow lard, grease, etc., when 
used alone, at 105-130 : F., according- to their ag-e, etc. Only 
aslig-htly hig-her temperature is required than would be neces¬ 
sary to keep the stock from solidifying- on running- in the 
cold lye, so that the proper temperature depends on the melting- 
points of the fats. In winter it is best to have the stock about 
10° F. hotter than in summer, and to have the lye at about 80° F. 

If the stock has not been prepared, i. e., the free fatty acids 
removed, or if rosin is used with the stock, it is necesary to 
use the lowest possible temperature, as the free acids cause con¬ 
siderable spontaneous heating- by their rapid combination with 
the lye. So also must a low temperature be used when the soap 
is hig-hly filled, and in summer the frames must then not be cov¬ 
ered very closely. 

If the temperature at which the ingredients are mixed is too 
high, those particles of the fat which were first to come into con¬ 
tact with the lye combine with the latter so rapidly that lumps 
form before all the lye is thoroughly mixed in, and, these lumps 
adhering to each other in a mass, the whole batch may be 
spoiled. 

It is also worth remembering that a low temperature pro¬ 
duces a whiter soap, while a higher temperature is more favor¬ 
able for a certain degree of transparency in the product. 

The lye is used in nearly all cases at the ordinary tempera¬ 
ture of the atmosphere, except in cold weather or for old stock, 
when it is made luke-warm. Some prefer to have both, stock 
and lye at the same degree, but it is difficult to see any advant¬ 
age accruing from the trouble of heating up the lye under ordi- 


Cold-Made Soap. 


281 


nary circumstances. On the contrary, a cold lye rather favors 
a greater smoothness in the finished soap. 

MIXING AND SAPONIFICATION. 

The actual saponification takes place only during 1 the course 
of spontaneous development of heat in the frame, and is barely 
induced while mixing. The stock, at the average temperature 
best suited to its composition—as just explained—is run into the 
mixing machine. This machine may be any vessel provided 
with a suitable agitating apparatus, and consists preferably of a 
jacketed kettle with a rapidly revolving agitator; the crutch- 
ing machines described in chapter V. are very suitable for the 
purpose. 

The object of this machine being simply to mix the fat and 
lye as thoroughly as possible, the best results are obtained by 
having the machine run at a good speed so as to complete the 
mixing quickly and keep the contents as homogeneous as possible 
while the lye is running in. For making colored soap, from 
well-purified stock, so as to admit of long crutching, an ordinary 
vessel and a hand crutch are frequently preferred, as it is difficult 
to clean a crutcher from the remnants of the colored soap. 

The stock being run into the crutcher (which should not be 
perfectly cold in winter time), the machine is started to crutch 
and the lye is run into the fat steadily in a thin stream at such a 
rate that it is all added in three or four minutes for a large batch. 
Crutching is continued uninterruptedly until the mass isobserved 
to thicken, so that a mark drawn on the surface remains visi¬ 
ble for some time and a sample taken out on a paddle runs 
off slowly and forms thick threads on the surface of the soap. 
Crutching is then discontinued and the soap run at once into a 
frame placed under the machine. Some experience is required 
to )udge correctly just when a soap of a given composition as to 
stock is in the best condition for framing; if framed too early 
the soap will afterwards be found smeary in the upper part and 
very sharp near the bottom of the frame, owing to part of the 
lye sinking; On the other hand, if the crutching is continued 
too long, or if too much time is allowed to pass before framing, 
the mass may separate in the frame and spoil the batch alto¬ 
gether; the same may happen if the ingredients were either too 
cold or too hot, or impure. 

Another proceeding which is preferred by some, although 


282 


Cold-Made Soap. 


it is difficult to see any advantage in it, consists in adding only 
about one-half of the lye at first; when the contents of the 
crutcher form a homogeneous mass the remainder of the lye is 
then added. 

The length of time necessary for crutching varies greatly, 
but the longer the stirring can be continued before the mass 
shows signs of requiring framing the finer will the grain of the 
soap become; in this respect also purified fats have an advantage 
over those not previously purified, as the former do not combine 
so rapidly with the lye. 

The frame into which the soap is run should not be too 
cold; nor should it be very high, especially if it is of large capac¬ 
ity, as it would retain too much heat. If the soap is run into a 
rather large flat frame and covered up with sacks or blankets it 
will become heated by the action of the ingredients on each 
other, and saponification will be effected without any further 
attention being required. In very hot weather cold made soaps 
—especially those highly filled—are liable to separate oil in the 
frame if covered up too warm; the temperature which a batch is 
allowed to acquire is therefore of much influence on the quality 
of the product and requires some study for each special case to 
obtain the best results. A soap of a certain composition which 
turns out well in a 300-lb. frame would be likely to show signs 
of separating oil in a 600-lb. frame, and would spoil entirely in 
a 1,200 lb. frame, owing to the greater heat prevailing in the 
larger batches. It thus follows, also, that whether the frame 
should be covered, and for how long, depends on the size of the 
frame, the temperature of the soap and of the atmosphere, and 
on the composition of the stock, as well as on the construction 
of the frame—whether of iron or wood. 

When the heat has ceased to be generated in a frame, the 
soap may be uncovered in order to cool off more quickly; after 
then hardening for a day or two it is ready to be stripped. In 
iron frames it must remain covered longer than in wooden ones 
which retain the heat longer; if uncovered too early the soap in 
the frame is apt to be of a different color in the centre than on 
the sides. 

A mixing machine has been patented which can be lowered 
into a frame so as to mix the ingredients therein, using no special 
mixing vessel. Ordinarly, however, some of the machines de¬ 
scribed in Chapter V. are used. 


Cold-Made; Soap. 


283 


FILLING. 

Cold-made soaps may be filled with any of the materials enu¬ 
merated and described in Chapter IV., by making the additions 
in the manner described for half-boiled soaps. Mineral soap 
stock, silicate of soda, and talc, are the fillers most commonly 
employed. The silicate of soda must be prepared with lye in the 
same manner as described for half-boiled soaps, or an equivalent 
excess of lye must be used with it. Such soap has a very nice 
appearance while fresh, but on drying out somewhat acquires 
a hard surface. As stated before, silicate, especially if it has not 
been previously prepared with lye is liable to cause separation, 
or spongy parts in the centre of the frame if the batch is large, 
so that for such soap it may be necessary to employ frames hold¬ 
ing as little as 200 lbs. each, and let the frames remain uncov¬ 
ered. When much silicate is used, however, the frames may be 
larger, probably owing to the fact that a larger addition tends to 
decrease the development of heat, by retarding the combination. 
The silicate, if added to the mass when the materials have joined, 
would thicken the soapso much that it could scarcely be handled; 
it is therefore generally mixed with the lye before stirring the 
latter into the fat, or it is mixed with the last portion of the lye 
used. A little glycerin or some 15 pearl ash solution is some¬ 
times used in addition to make such soap a little smoother. Talc , 
wuich may be used in as large a proportion as 25 or 30 per cent 
and over, gives the soap a somewhat dull appearance, in white 
as well as in colored soaps, but it also makes it less hard on aging 
than one containing silicate with which it is sometimes used 
together; some manufacturers prefer to boil the talc in a little 
weak lye before adding-it, claiming that this “opens” the talc 
and makes the product smoother. Others prefer to simply mix 
the talc with the oil before running the lye into the crutcher. 

For cheap soaps made largely of cocoanut oil, solutions of 
salt, potash, and chloride of potash are largely employed as fill¬ 
ers in Europe, since cocoanut oil has the property of absorbing 
these solutions in considerable quantities without separating. 
These solutions are usually crutched in when the soap has thick¬ 
ened so as to be nearly ready for framing, and are mostly em¬ 
ployed at a strength of from 15° to 25 B. Saltwater makes the 
soap hard on drying and causes it to feel moist if added in more 
than moderate quantities. Chloride of potash is more expensive, 
but retains the water of the soap better than does common salt. 


284 


Cold-Made Soap. 


In fact, these filling’s must be regarded as simply water, to 
which the salts are added for the purpose of counteracting the 
softening effect which simple water has on soap. Potash solu¬ 
tion especially prevents the drying of soap filled with salt solu¬ 
tion or silicate, so that potash and salt are generally used to¬ 
gether; they also give the soap a more transparent appearance, 
and, used moderately, they enhance the whiteness of cold soaps 
which otherwise turn yellowish on storing. 

In European countries cold-made cocoanut oil soaps are also 
very frequently filled by so-called filling lyes, which are made 
according to the following examples, and which are used to the 
extent of from 10 to 50 lbs. to every 50 lbs. of cocoanut oil in 
the stock: (1) 100 parts water, 14 parts sugar, 7 parts salt, 7 
parts pearl ash. (2) A 16 c B. solution of chloride of potash, sal 
soda and salt (equal amounts of each). (3) One part each of 
sugar, potash and salt dissolved in 4 Y? parts of boiling water. 
(4) 85 parts hot water, 9 parts pearl ash, 6 parts salt, 5 parts sal 
soda. 

In using these filling lyes the cocoanut oil should not be 
used warmer than necessary, and the frames are not covered, as 
the soap would become too hot if covered and would separate oil 
in the centre. The oil and lye are first mixed, and when the 
soap is thick and appears ready for framing the filling lye is 
crutched in. 

Where these salts are used for filling it is so much more im¬ 
portant, of course, that the lye be made of the highest grades 
of caustic. If, on pressing, the soap should show a tendency to 
crack, as is liable to be the case when much filling is employed, 
the cakes must be warmed somewhat to soften them before 
pressing. 

PERFUMING, COLORING, MARBLING. 

If properly prepared stock is used, the essential oils for per¬ 
fuming may be crutched into the soap just long enough before 
framing to secure their intimate admixture, so as to avoid all 
unnecessary evaporation during the crutching operation, as well 
as the action of the lye on the oils. With unprepared stock it 
may be necessary to add the oils together with the last of the 
lye. 

If powdered orris root is added, and it is found to make the 
soap too dr} 7 and brittle, some of the soda lye should be substi- 



Coi.d-Madk Soap. 


285 


tuted by potash lye, or the lye is used a little weaker. Orris root 
turns the color to yellow or yellowish brown. It should also be 
remembered that oil of cloves has a peculiar composition, different 
from other essential oils, and that it is therefore not well suited 
for soaps made by the cold process, as it interferes with the com¬ 
bination of the materials, and at all events gives the soap a bad 
grain and texture and a yellowish color; the latter case is also 
true in regard to cassia oil, which makes these two oils unsuit¬ 
able for white soap. (For further details see the chapter on 
Perfuming and Coloring.) 

Insoluble colors, such as vermillion, are well mixed with a 
portion of the oil, and added to the stock from the start; soluble 
colors, such as annatto, aniline, etc., are dissolved in boiling wa¬ 
ter, or in alcohol, and strained through a silk cloth into the stock 
or the lye, to avoid specks of undissolved color. Of the soluble 
colors much smaller quantities are ordinarily required than of the 
soluble ones. 

For yellow soaps a little unbleached palm oil may be used 
with the other stock. Palm oil in conjunction with orris root 
and storax causes a natural and permanent reddish brown color 
which makes this combination popular for cold-made violet soap. 

White soaps must not be too warm on cutting up the frames, 
as they are liable to become discolored on exposure to the air 
when warm. The addition of just a trace of ultramarine will 
change the yellowish tinge of most white soaps into a less notice¬ 
able greenish color. 

For making marbled or variegated soap by the cold process, 
the water soluble colors are not well adapted, as they run too 
much. Numerous processes are employed to produce the marbled 
appearance; for instance, the soap may be run into the frame be¬ 
fore it has become quite so thick as usual. A sheet iron cylinder, 
open at both ends, is then sunk into the frame and the soap 
within colored through the upperend of the cylinder. A wooden 
stirrer is then used to draw the colored soap into the uncolored 
portions in streaks, and, lastly, by means of a rod with a round 
knob on the end, figures are drawn through the whole frame. 

Another method consists in mixing the colors with a little 
oil or warm water and stirring this into a small portion of the 
soap, when thick. A layer of soap is now run into the frame, 
and the colored soap is spread over it “criss-cross” in a thin 
stream (as by running it through the stem of a funnel, or a sprink- 


286 


Cou>Madk Soap. 


ling- can with larg-e holes). Then follows another layer of the 
soap, and again streaks of the colored soaps. When the frame 
has thus been filled by alternate layers, a stick is used to distri¬ 
bute the color in the soap more finely, as described above. 

Where the mixing vessel is such that it can be tipped to 
empty it into the frame, the soap in the upper part of the vessel 
only may be colored, and the whole then emptied quickly b}^ 
tilting the vessel, so as to run both the colored and the uncolored 
portion out alongside of each other. 

Still another method is as follows: The color is mixed with 
a portion of the soap and a layer of it poured in streaks over the 
surface of the soap in the frame. It is then forced to the bottom 
by means of a JL formed crutch, in the bottom piece of which 
there are a number of holes. Another layer of colored soap is 
then treated similarly, and so on till all the color is added. A 
rod is then used to distribute the color still further. 

FORMULAS FOR VARIOUS COLD-HADE SOAPS. 

Although the preceding pages contain all the necessary in¬ 
formation required for building up a formula to make a soap to 
suit every purpose, a few ready formulas will probably be found 
useful by way of illustration. The following are selected to 
show those of the most varied character, and manufacturers who 
desire to do so can readily modify the same to suit their own re¬ 
quirements by giving due consideration to the effect of different 
materials and manipulations, as has been fully explained. 

PURE COCOANUT OIL SOAP. 

300 lbs. cocoanut oil. 

150 “ caustic soda lye, 38 B. 

This soap lathers very readily, and if carefully prepared 
Cochin oil and well settled, clear lye are used, the soap will be 
almost semi-transparent. The lye may be reduced in strength 
by adding water, until it marks 35-36 B., which will make the 
soap somewhat smoother and softer; a small extra addition of lye 
will harden it again and will bring about a more complete sapon¬ 
ification, so that the soap will preserve its white color longer. 
By reason of the better saponification this extra strength will 
not be very noticeable, especially as a pure cocoa nut oil soap 
can be used (for toilet purposes) only by those whose skin is not 
very delicate, it being too sharp for tender skins, even if quite 
neutral. 


Cold-Made: Soap. 


287 


As the lather is almost too profuse, and the soap wastes 
away quickly, a small proportion, say 10%, of castor oil may be 
desirable, as this addition also improves the texture and trans¬ 
parency of the soap. 

FILLED COCOANUT OIL SOAP. 

The above soap may be filled with silicate, talc, etc., if de¬ 
sired, in accordance with the directions already given for half- 
boiled soap, and in the special chapter on filling- materials. 
About 60 lbs. of silicate (prepared as previously stated), with or 
without the further addition of 15 lbs. potash solution mig-ht be 
used; or, if preferred, say 35 lbs. of talc. 

COCOANUT OIL SOAP, FILLED WITH SALT SOLUTION. 

300 lbs. cocoanutoil. 

150-160 “ soda lye, 38° B. 

30-150 “ salt solution 18 B. 

Or, 

300 lbs. cocoanut oil. 

150 “ lye 39-40° B. 

25 “ potash solution 20 B. 

12 “ salt water 16 c B. 

In the above two formulas the oil is melted (at about 80- 
F.) and 135 lbs. of the lye crutched in. When the mass is thick¬ 
ening- the remainder of the lye, mixed with the salt solutions, is 
added. 

If some castor oil is preferred in the soap, it may be added 
to the cocoanut oil, and the filling- may be varied according to 
the following formula: 

300 lbs. cocoanut oil. 

30 “ castor oil. 

162 “ soda lye 38 B. 

24 “ potash solution 20 B. 

18 “ potassium chloride solution 15 B. 

TALLOW AND COCOANUT OIL SOAP. 

240 lbs. cocoanut oil. 

160 “ tallow. 

200 “ soda lye 37 B. 

The manufacture of this soap is the same as that of the 
pure cocoanut oil soap described, only the temperature of the 


288 


Cold-Made Soap. 


stock must be a little higher, say 100° F. The tallow will cause 
the soap to be less wasteful and to lather less quickly than a 
pure cocoanut oil soap, and will ordinarily reduce the cost some¬ 
what. 

Another formula, in which some potash lye is used, and a 
little less (> 2 ) cocoanut oil, may be adopted, as follows: 

250 lbs. cocoanut oil. 

250 “ tallow. 

240 “ caustic soda lye 38 B. 

10 ‘‘ potash lye 38° B. 

A filled soap which in the eyes of some customers has a better 
appearance even than the foregoing pure soap, can be made by 
changing the formula as follows: 

240 lbs. cocoanut oil. 

160 “ tallow. 

200 soda lye 40° B. 

60 “ potash solution 20^ B. 

20 “ salt water 18° B. 

A soap of different character results from the following: 

275 lbs. lard. 

175 “ cocoanut oil. 

225 “ 36° soda lye. 

Or, 

100 lbs. cocoanut oil. 

50 “ tallow. 

50 “ lard. 

50 “ castor oil. 

120 “ 38° soda lye. 

5 “ 26 potash lye., 

Or, 

(For yellow soap.) 

160 lbs. cocoanut oil. 

120 “ tallow. 

20 “ palm oil (unbleached). 

150 “ soda lye 37° B. 

The following two formulas and process of making some¬ 
what similar soaps are furnished by a firm familiar with this 
class of work. 


Cold-Made Soap. 


289 


75 lbs. tallow. 

25 “ cocoanut oil (Ceylon). 

75 “ caustic soda lye, 35^4° B. madeof 74%caustic. 
125 “ “N” silicate of soda. 

20 “ pearl ash lye, 36° B. 


320 “ soap. 

Or, 

75 lbs. tallow. 

25 “ cocoanut oil (Ceylon). 

70 “ caustic soda lye, 35}4 ° B. madeof 74% caustic. 

100 “ “N” silicate of soda. 

17 “ pearl ash lye, 36° B. 

287 “ soap. 

Process. 

Cleanse the tallow by boiling- on salt brine or a weak solu¬ 
tion of alum; let tallow settle after boiling-, to deposit all impur¬ 
ities in the usual manner. 

Weig-h out the proportion of tallow and cocoanut oil required 
for a frame of soap into a tig-ht frame. Weig-h out the quantity 
of caustic soda lye required into a separate vessel. Also weig-h 
out the proportion of silicate needed into another vessel; also 
weig-h out the pearl ash lye wanted, which can be mixed with 
the silicate. 

When all is ready for mixing-, the tallow and cocoanut oil in 
frame must be at a temperature of 145° to 150° F. in cAd weather, 
and 125° to 130° F. in warm or summer weather—the lye and 
silicate both to be at the normal temperature of factory. When 
the temperature is as above, run in the lye alone into the tallow 
and cocoanut oil in frame quickly, crutching- rapidly from bottom 
of frame all the time. After the ly^e is all in, continue crutching- 
rapidly till the soap beg-ins to thicken up. Now run in the sili¬ 
cate and pearl ash lye quickly, crutching- rapidly. As the sili¬ 
cate mixes with the soap, the whole will thin out. After the 
silicate and pearl ash lye are in, continue crutching-. In a few 
minutes the whole will gradually turn creamy. As soon as the soap 
becomes so thick or creamy that a mark made on surface of soap 
will remain, it is finished; take out crutchers, cover up frame, 
and do not move or disturb frame till soap is cold. Any perfume 
used must be added while crutching- in silicate. 




290 


Cold-Made Soap. 


If the frame must be moved from where the soap is made, 
move it quickly before the silicate is added; then add the silicate 
at once, and finish soap as directed. 

This is essentially a quick process, everything’ must be done 
quickly. For a 1,000 lbs. frame, the lye must be run into the 
grease material in from 90 to 120 seconds—silicate about the 
same. Crutching must be done quickly and go to bottom 
each stroke—work two crutches. Never stop crutching from 
start to finish. The time for making frame (if the temperatures 
are right) from 12 to 16 minutes. Great care must be taken not 
to crutch too long. To insure a smooth soap, stop as soon as a 
mark made on surface of soap will remain. Under no circum¬ 
stances move or shake the finished frame of soap until cold. 

30% to 53% of refined cotton seed oil can be substituted for 
an equal weight of tallow, if tallow is hard. If tallow is soft or 
mixed with grease use less oil. The soap will not be quite so 
hard, will take longer to harden, and will be a good washing 
soap. 


GLYCERIN SOAP. 

Some soaps are called glycerin soaps by the manufacturers 
on the strength of the little glycerin only which forms during 
the saponification of the fat. There is however, also a class of 
soaps to which some extra glycerin is added, which increases 
the emollient feeling of the soap and preserves it longer against 
drying out. Too much glycerin, however, causes sweating and 
makes the soap smeary. 

The glycerin is mixed with the melted stock and the mixture 
saponified in the ordinary manner. If silicate is to be added it 
may be crutched in after the materials have joined, together 
with the necessary lye required for preparing the silicate, as the 
glycerin naturally thins the soap out somewhat. If only little 
glycerin, or much silicate is used, the latter may be previously 
mixed with the last of the lye added to prevent the soap from 
thickening too much. 

The following is one of a great number of similar formulas: 

120 lbs. cocoanut oil. 

40 “ lard. 

40 “ tallow. 

40 “ glycerin. 

100 “ lye 38° B. 


Cold-Made Soap. 


201 


The fats are melted, and the glycerin added. At about 100° 
to 110 F. the stock is saponified with 100 lbs. 38° lye. 

LANOLIN SOAP. 

60 lbs. cocoanut oil. 

5 “ Lanolin (Adeps lanae). 

30 “ Soda lye 38° B. 

Melt the cocoanut oil, add the lanolin to it and crutch till 
homogeneous, then proceed as usual to add the perfume, color 
and lye. This method is preferable to melting the lanolin di¬ 
rectly, as the latter readily turns dark on heating it. 

The soap can be further improved and modified by adding 
to the stock some air-bleached palm oil (and of course a corres¬ 
ponding amount of lye), and possibly also some glycerin. 

The amount of lanolin may be increased or decreased with¬ 
out changing the amount of lye, as it is not saponifiable. 

LAUNDRY SOAPS. 

The foregoing formulas are principally intended for toilet 
soaps. For laundry soaps a smaller proportion of cocoanut oil 
is used, as the latter is expensive, and the soap wastes away too 
fast. Naturally, no close distinction can be made between soaps 
for the two purposes,except, of course, so far as perfuming them 
is concerned; but the following formulas will be found to be better 
adapted for household soaps than for toilet purposes: 


350 lbs. tallow. 

150 

“ grease. 

100 

“ cocoanut oil. 

35 

“ mineral soap stock. 

400-435 

“ soda lye 35° B. 

300 

“ silicate of soda. 


The mineral soap stock is melted with the fats, at about 120 c 
F. The silicate is dissolved in the lye, and the latter run into 
the crutcher while the machine is running briskly. The perfume 
may be added with the last of the lye. The addition of the lye 
requires less than five minutes, and, after crutching for a short 
time longer, the soap will have acquired the proper consistency 
for framing. 

This formula may, of course, be changed in many ways, as 
regards stock as well as filling. A formula, for instance, which 
gives satisfaction in many localities, is as follows: 


292 


Cold-Made Soap. 


220 lbs. tallow. 

35 “ cocoanut oil. 

165 “ soda lye, 34 B. 

125 “ silicate of soda. 

Still another formula is as follows: 

330 lbs. cocoanut oil. 

170 “ tallow. 

250 “ soda lye, 39°, diluted with 
30 “ water. 

350 “ filling', made by dissolving’ 2 parts sal 

soda, 1 part pearl ash, 2% parts salt, in 20 
parts of boiling water. 

For soaps of this kind, as before mentioned, small and low 
frames are the most suitable. 

ROSIN SOAP. 

As rosin consists of free acids, its presence in the stock 
causes some difficulty in use of the cold process, as pointed 
out previously. But this may be overcome fairly well by suit¬ 
able manipulation. (If desired, the rosin may be purified as de¬ 
scribed on page 69.) 

The following are several formulas which have been used 
for the purpose. 


100 

lbs. 

cocoanut oil. 

100 

lbs. 

tallow. 

200 

lbs. 

rosin. 

200 

lbs. 

lye 39° B. 



Or, 

100 

lbs. 

cocoanut oil. 

100 

lbs. 

tallow. 

25 

lbs. 

rosin. 

112 

lbs. 

lye 37° B. 

20 

lbs. 

talc (stirred into the stock). 



<9r, 

50 

lbs. 

tallow. 

50 

11 

palm oil. 

20 

t i 

rosin. 

55 

t ^ 

lye 40 B. 

50 


silicate of soda. 


Cold-Made Soap. 


293 


Or, 

255 lbs. tallow (or bleached palm oil). 

45 “ cocoatiut oil. 

45 “ light rosin. 

181 “ 38° lye. 

181 “ 38° silicate of soda. 

The fat and rosin are melted together, strained, and sapon¬ 
ified, the crutcher running rapidly, and the lye—mixed with the 
silicate, if any is used—being added slowly; if run in too fast or 
too warm, the soap will work over. Another method of making 
these soaps which is capable of giving good results is as follows: 
Taking the first of the above three formulas as a basis, the stock 
is melted and worked together with the 150 lbs. of the lye; scraps 
that are to be worked up may also be added in small pieces, and 
the whole is melted together. In another vessel the 200 lbs. 
rosin are melted on 60 lbs. of the lye, and when all the scraps 
have become melted the rosin mixture is run in slowly while 
crutching rapidly. The soap must be framed quickly. The lye 
may have to be diluted somewhat, owing to the dryness of the 
scraps and the water evaporated during melting. 

A modified process has lately been proposed, as follows: 

80 lbs. cocoanut oil. 

80 “ tallow. 

180 “ 21° soda lye, mixed with 

20 “ 32° potash solution. 

40 “ 38° silicate of soda. 

The fat is mixed with the lye at the ordinary temperature 
of the atmosphere (60°); then the slightly warmer (72°) silicate 
is added; the mass then separates. Crutching is continued till 
all is uniformly dissolved when two pints of strong alcohol are 
added, which causes the ingredients to join at once. The soap 
thickens and must be framed quickly. 

TAR 50AP. 

160 lbs. cocoanut oil. 

40 “ tallow. 

40 “ wood tar. 

120 “ soda lye 37B. 

20 “ glycerin or vaseline. 

The fat, tar, and glycerin are warmed up together, and the 
lye crutched in in the ordinary way. The addition of the glyce- 


294 


Cold-Made Soap. 


Remelting. 


Milling. 


rin permits longer crutching and thereby a more complete mix¬ 
ing-. If the soap should separate, warmth and rest will soon 
close it ag-ain when it may be rapidly crutched and framed. Part 
potash lye in place of an equivalent portion of soda lye is advis¬ 
able in case no vaseline or glycerin are used. 

^CARBOLIC SOAP. 

120 lbs. cocoanut oil. 

60 “ tallow. 

90 “ soda lye 38° B. 

2^4 “ potash lye 25° B. 

1 “ crystallized carbolic acid, dissolved in 

2/4 “ water. 

A suitable perfume for this is: oils of lavender 2 parts, 
white thyme and fennel 1 part each. 

UTILIZING SCRAPS OF COLD SOAPS. 

The profitable utilization of scraps is one of the difficult 
problems of the manufacturers of cold soaps. 

The most feasible plan is usually the remelting- of the same, 
as described in Chapter XIV, dealing- with this operation. For 
factories making-no soap at all by boiling-, this is the more to be 
recommended, as some remelting- apparatus are excellently 
adapted also as mixing vessels for the manufacture of soap by 
the cold process. Where a practicable remelter is not among the 
machinery in the factory, the scraps are sometimes melted on 
lye of 24-30° B. and the excess of strength is then absorbed by 
crutching in an equivalent proportion of cocoanut oil. 

The scraps may also be remelted in a jacket kettle, by hav¬ 
ing an open steam pipe leading directly into the soap, keeping 
the kettle covered up while the open steam is turned on, to pre¬ 
vent the same from throwing out the contents. By the open 
steam and that in the jacket, assisted b} T occasional stirring, the 
scraps are slowly melted. There are then added some salt water 
and some pearl ash solution, both at about 22° B. (according to 
the moisture already present in the soap), and in quantity de¬ 
pending on the composition of the soap, especially as to its pro¬ 
portion of cocoanut oil. To 150 lbs. of a pure cocoanut oil soap 
as high as 50 lbs. of each of the solutions may be added. 

Another use which may be made of the scraps is for milling, 
if the necessary machinery is on hand. They must be dried for 


Cold-Made Soap. 


295 


this purpose, like other soap for milling’, and may be profitably 
mixed (especially cocoanut oil soaps) with about S% of starch, 
which will make them more agreeable in use than ordinary cold- 
mixed soap, or with some talc. For this purpose different colors 
and qualities of scraps are kept separate, and suitably perfumed 
in milling. 

A use which is sometimes made of such scraps in some Euro¬ 
pean countries is for so-called Mosaic-soap, which is made by 
making a batch of cold soap of a certain color, and when almost 
ready to frame, adding the scraps of another color, cut into small 
pieces and mixing them in well. White scraps are thus mixed 
with red and brown, and yellow soap, and vice versa. For this 
purpose scraps colored with aniline colors are not well adapted 
as the latter has a tendency to spread into the white soap. 

Another method is a combination of some of the foregoing, 
as follows: 200 pounds of tallow are melted to 185° F. and 325 
lbs. of scrap (free from silicate filling) are then melted in the 
hot fat. Soon after the mass reaches a temperature of 185 F. 
again, the scrap will be melted, and the whole is strained into 
the jacket kettle or crutcher; 110 lbs. of 34 B. lye are then 
crutchedin. The soap will at first be inclined to form lumps, 
but thins out by continued crutching. At this stage, some hot 
water, in which the color has previously been dissolved, must be 
added, before the soap thickens again. After the lye has all 
been added, about 45 lbs. potash solution of 25 B. are crutched 
in. When the soap forms a short, thick mass, it is framed. If 
the scraps were taken from unfilled soap, the potash solution 
may be added at once, on melting the scraps, instead of waiting 
until the lye has been mixed in. Scraps filled with silicate can¬ 
not be so treated, as the filling would be decomposed, and sand¬ 
like grains would make their appearance. 

A simple, but not altogether satisfactory way, consists in 
simply adding the finely cut scraps to the next batch of similar 
soap just before framing. 

The cold process may also be employed for making soft soap, 
by using soft stock and potash lye instead of soda lye. It is un¬ 
necessary to give a detailed description of the same, however, 
as there is little call for it, and the details will readily suggest 
themselves from the special chapters on Soft Soap and on the 
Cold Procees. 


Mosaic soap. 


Another method. 































. 




































. 
















































PART III. 















CHAPTER XIV. 


Remelting Soap. 


When soap that has been hardened by cooling- is subjected 
again to a warm temperature, it will assume a thickly fluid con¬ 
sistency similar to that which it originally had when framed. 
Advantage is taken of this property for melting over the trimm¬ 
ings left from cutting up the frames of soap, or for working over 
any soap which may have become “cracky” in the frame, or 
which is unsalable for any other reason. 

In England remelting is also largely employed for making 
toilet soaps from stock soaps which the soap manufacturer furn¬ 
ishes to the perfumers and others for remelting, coloring, per¬ 
fuming, etc. This practice was the natural outgrowth of the 
excise regulations governing soap factories formerly in force in 
England; but in the United States remelting is practically con¬ 
fined to the utilization of scraps and faulty soaps, as stated above, 
or for making small batches of floating soap. 

In factories where soaps are made by boiling, the scraps 
may be utilized in the manner described at the close of Chapter 
VII (Settled Soaps), but owing to the reasons there explained, 
remelting is greatly to be preferred. During remelting the soap 
assumes a condition in which the use of a small amount of extra 
filling is not only possible, but even advisable, inasmuch as this 
“closes up’-’ the melted mass, giving it a more even and solid 
texture—besides increasing the weight of the soap. 

For factories making soap only by the cold process, remelt¬ 
ing is really the most feasible plan for utilizing the scraps. 

The manner of remelting necessarily varies with the ma¬ 
chinery employed for the purpose, and it may here be remarked 




300 


Remeeting Soap. 


Soap a bad con- 
ductoi' of heat. 


that practical soap makers are by no means equally successful in 
the use even of the same machines for this purpose. The differ¬ 
ent apparatus described in Chapter V, as used for remelting, 
give good results when correctly used. More than on the ma¬ 
chinery, however, the results depend on the character of the 
soap to be remelted and on the judgmentexercised in the operation, 
especially when the soap contains much filling. The principal 
point to remember in remelting is that soap is a bad conductor of 
heat. For this reason the operation must either be allowed plenty 
of time, or the remelted soap must constantly be moved away 
from the steam-heated parts of the apparatus, so as to make 
room for the unmelted scraps directly near the hot parts of the 
machinery. All attempts to hurry the process will be unsuccess¬ 
ful if the arrangements are not such that the scraps are directly 
in contact with the source of the heat. 

Referring to the various illustrations in Chapter V, the pro¬ 
cess of remelting is conducted as follows: 

The machine is filled with the scraps and the kettle covered 
up (or the curb described in Chapter V is used), in order to pre¬ 
vent the steam from escaping into the room, and to thoroughly 
moisten the soap; open steam is then admitted into the contents 
until the scraps are beginning to melt. 

Scraps that have become well dried before remelting will 
melt less easily than soap still containing a considerable propor¬ 
tion of water; with the latter it may not be necessary to add any 
open steam at all. When toilet soaps are made by remelting 
stock soaps (cut into shavings for the purpose), it may also be 
best not to use open steam, as these soaps are generally intended 
to contain but little water, so that they may resemble milled 
soaps as much as possible. If a combined crutcher and remelter 
is used for making a toilet soap by remelting, without the use of 
water or open steam, the conveyor screw should run very slowly. 
Half a day or more is required in this case for remelting a frame 
of soap. For ordinary uses, with the aid of open steam, the 
operation proceeds much more rapidly, however. 

When the soap is observed to begin melting, the open steam 
is shut off and the closed steam turned on, so as to heat the iack- 
et, or coils, as the case may be. In the Whitacre remelter (Fig. 
43) the soap, as it melts, is run off into the frames, and the con¬ 
tents of the latter occasionally stirred up, to insure uniformity 
of the mass, or the soap is run into the crutcher for mixing. If 



Remelting Soap. 


301 


the machine used is a combined crutcher and remelter, more 
scraps are added as the soap melts down, and the crutcher started 
for a few minutes until the melted soap and the fresh scraps are 
well mixed. Closed steam is then again turned on to melt the 
soap completely. 

The open steam should be employed in such manner that it Open ste;u». 
supplies only enough water for giving the remelted soap the or¬ 
iginal appearance and consistency of a newly made soap, and no Crntchiug. 
more crutching should be done than is required to secure even 
melting of the scraps; too much crutching will make the soap 
frothy by incorporating with it air bubbles, which will cause it 
to float. The same defect results also if the soap is crutched 
long when very thick, or if it is heated for too long a time, 
whereby it undergoes a peculiar alteration in its texture. Ex¬ 
perience is here again the only reliable guide. 

Care must, of course, be taken that no unmelted pieces re¬ 
main, as they would cause aspotted appearance, especiallv if col¬ 
oring matter or filling is to be added. 

After simply remelting, the soap has not exactly the same Additioiiad fiiiiug. 
appearance and consistency as the original soap from which it 
was made, and to improve it in this respect some filling is gener¬ 
ally added while crutching, after enough soap for a frame has 
been melted. 

The filling may be used similarly as in framing the original 
soap, and consists of various salts in saturated solutions—as, 
carbonate of soda, sulphate of soda, borax, salts of tartar, com¬ 
mon salt, bicarbonate of soda, carbonate of potash, etc., accord¬ 
ing to circumstances. A favorite material, especially in good 
soaps, is pearl ash (carbonate of potash) dissolved in water, which 
causes the simultaneous formation of carbonate of soda and of 
potash soap in the mass, thereby very noticeably improving the 
texture of the product. (This change is similar to that men¬ 
tioned under “Potash,” in Chapter III, and further explained in 
note 11 of the Appendix.) 

For a good toilet soap such an addition of filling is, of course, 
out of place, and, in fact, toilet soaps are best made by milling, 
which is the usual process in this country; while the cheaper 
grades of this kind are generally made by the cold or the half- 
boiling process. 

The stock for remelted toilet soaps would have to be selected 
according to the product to be made. A settled soap made of 


302 


Remelting Soap. 


tallow and a small proportion of rosin, a small proportion of co- 
coanut oil soap—to increase the lathering- properties—white 
curd soap, and, perhaps, also some soft potash soap, may be 
blended tog-ether by remelting-, in proportions to suit. A clos¬ 
ing- mixture, consisting- of a saturated solution of say 12 lbs. 
pearl ash is then crutched in for .every 1,000 lbs. of soap, and 
the color and perfume added. The mass is then run into frames. 


CHAPTER XY. 


Milled Soaps. 


General Remarks. 


Of all soaps made those properly prepared by “milling-” are 
the best in many respects. In point of intrinsic merit as a soap 
they are preferred because they contain the least possible amount 
of water, and are usually prepared from the best materials, and 
with the greatest care; besides every well-made soap is improved 
by repeatedly re-working- it. Owing- to the extra time, the 
special machinery, and the quality of the ingredients required 
to make the really g-ood kinds of the milled soaps, they are nat¬ 
urally somewhat more expensive; but they are also more lasting- 
in use, because their small proportion of moisture and their dense 
texture make them waste away less quickly, while in point of 
neutrality and delicacy of perfume they are unequalled by any 
other soap. In appearance also, which is a not unimportant 
item in a toilet soap, they are beyond comparison, for the pro¬ 
cess by which they are manufactured g-ives them a hig-h finish 
and preserves them from shrinking-, no matter how long-they are 
kept. 

These remarks, of course, refer only to those soaps that have 
been made with that care and of such purity as are looked for by 
the buyer of milled soaps; they do not apply at all, or at least 
not in the same degree, to those milled soaps, for instance, that 
are sometimes made from a cold-mixed soap, either for the pur¬ 
pose of working- up the scraps, or for the sake of merely g-iving- 
a cold-made soap the appearance of a milled soap; nor do they 
apply to some boiled soaps whose ingredients or manufacture 
have been faulty. 


Superiority of 
milled soap. 





304 


Milled Soaps. 


The process of milling - itself is merely a mechanical opera¬ 
tion to which a well-boiled soap is subjected, but the improve¬ 
ment effected by it is quite important. It consists in preparing* 
the soap by dr}dng until only enoug*h moisture is left to enable 
it to form a compact cake, grinding - it between rollers to make it 
perfectly homog - eneous, and adding - to it—while grinding - —the 
perfumes and colors, whereby the admixture of these ingredients 
is made not only more intimate, but also at a considerable saving 
of perfume, of which more or less would be lost by evaporation 
if crutched into the hot soap. An additional advantage arises 
from the exposure of the shavings to the air for drying, during 
which any free caustic alkali that may be present is converted 
into the less corrosive carbonate by the absorption of carbonic 
acid from the atmosphere. Incidentally, however, milling also 
offers an opportunity for greatly adulterating soap; by the use of 
starch, talc, and other dry powders, a well-appearing piece of 
soap may be made even if the stock soap is not quite dry. In an 
emergency, when the pure soap is troublesome in milling, the 
addition of from 5 to 10% starch will frequently be very help¬ 
ful; but for purposes of adulteration the addition is some¬ 
times increased to as high as 30 or 40 per cent. So also the pro¬ 
cess of milling may be used to incorporate into the soap such 
special ingredients for special purposes as vaseline, lanolin (or 
other wood fat preparations), &c. 


Early methods of 
milling. 


The process of milling originated in France, where it was at 
first carried on in the following primitive manner: 


The soap was made into shavings by drawing the bars 
across an ordinary carpenters’ plane so placed—cutting edge up¬ 
ward—over a marble mortar, that the shavings fell into the 
latter. In the mortar they were pounded into a doughy mass, 
and the color and perfume rubbed in by means of a wooden pestle 
and several hours of hard work. Small quantities of the mass 
were then weighed out to form cakes of the desired size, moulded 
by hand into a form approaching that of the cake, and after dry¬ 
ing for a day pressed by means of a hand press. The soap so 
made soon gained a wide reputation, in consequence of which 
the special machinery for making it in large quantities has been 
perfected, and milled toilet soaps now have a world-wide reputa¬ 
tion and are manufactured wherever soap making has become an 
important industry. 


Milled Soaps. 


305 


STOCK FOR HILLED SOAP. 

Only fresh and pure fats and oils are suitable for this pur¬ 
pose, for the delicate perfumes and colors would lose the princi¬ 
pal part ol their value, if combined with a soap of the peculiar 
odor and appearance arising* from old or low-grade fats. It is 
also necessary that the fat be most thoroughly saponified, for 
any free fat remaining would soon cause rancidity in the soap 
and thereby spoil the perfume. No amount of care in milling 
can save the soap from deteriorating and the odor from becoming 
disagreeable, if the soap itself was not well-made in boiling. 
Trouble of various kinds arising during the process of milling 
also is in most cases due to faulty manipulation in finishing the 
boiling, for unless the soap has been very thoroughly settled, it 
will not adhere together after milling. A good soap for milling 
should not be too short and brittle, and while it is still fresh it 
should adhere together on kneading it between the fingers, like 
soft, tough clay. 

Tallow, or bleached palm oil, and from 10 to 20% of cocoa- 
nut oil make the most desirable stock for a soap that is to be 
made into a milled toilet article. Olive oil and olive oil foots 
also form soap of a desirable quality for milling and are used to 
quite an extent for this purpose. The fats are saponified by 
boiling repeatedly with lye and then settling carefully. The 
process for making a “White Settled Soap,” asdescribed on page 
205, etc., is excellent for this purpose. The fats are saponified 
in the first change, so that the soap remains sharp after boiling 
for half an hour, without the addition of more lye; it is then 
grained, not too strongly, but so as to just separate the waste 
lye clear on the paddle. After a sufficient rest the lye is run off, 
the mass closed up again with weak lye of say 8°, and boiled for 
an hour or two. It is then again grained by strong lye of about 
35°, this time so as to have a somewhat sharper grain. The lye 
is drawn off again after a rest of several hours, and saved for 
use in laundry soap, and by means of boiling water and open 
steam the soap is then thinned out for settling; it should not be 
thinned quite so far as to close up completely like a rosin soap, 
but only to form a very flat grain. After resting as long as pos¬ 
sible, the clear soap is framed. 

In regard to properly settling soap that is to be milled after 
ward, there is much diversity of opinion arising from the fact 


Saponification. 


Settling. 


306 


Milled Soaps. 


Special stock. 


that, when no starch, rosin soap, or other binding’ material is 
used, the soap will be cracky on coming from the plodder, unless 
the nigre and foreign salts have been settled out very thorough¬ 
ly. In order to remove these impurities as nearly absolutely as 
may be, different means are adopted by different soap makers, 
and this is one of those particulars in which the most expert 
have “agreed to disagree” most decidedly. Most manufacturers 
simply settle the soap as just described, making as large batches as 
possible at a time, in order to give the soap the benefit of as long 
a rest as possible to drop the impurities, and using, if necessary, 
some special ingredients to secure greater cohesion between the 
particles of soap in case it is defective in this respect. 

Others hold that the presence of some pearl ash or soda ash 
in finishing the soap contributes to a more thorough settling out 
of the impurities, and accordingly they adopt this method of 
settling soap intended to be milled. 

Again, still another proceeding is used by some well-known 
manufacturers of first-class soap which consists in running the 
hot soap into wooden frames, and allowing it to drop the nigre 
there. When the soap has hardened and is cut up, it is found 
that the nigre has been forced upward toward the center of the 
frame, where it is plainly visible, and may be cut out. The 
cause of the rising of the nigre in this manner from the bottom 
of the frame is not as yet fully explained, but it may be com¬ 
pared to a similar action which sometimes occurs in the kettle 
after steam has been turned off and boiling ceased. This pro¬ 
cess makes it necessary to return on an average about one-third 
of the soap into the kettle, and is consequently somewhat un¬ 
pleasant and laborious, but the pure soap obtained is in a first- 
class condition for milling. 

At any rate, if on cutting up a frame nigre is found in spots, 
such pieces should be at once rejected, as after drying they are 
hard to identify. 

A palm oil soap made in a similar manner as described above, 
from bleached or unbleached palm oil, is a very useful one for 
milling purposes, as is also a cotton seed oil soap which may be 
used to advantage as an addition to other kinds, when the soap 
in the plodder does not work satisfactorily. The advantage of 
using some castor oil in soap for milling has already been men¬ 
tioned in the description of that oil. 

Where scraps of cold-made cocoanut oil soap are to be worked 


Milled Soaps. 


307 


up by milling, it may sometimes be done to advantage by using 
a soap boiled from tallow alone. 

THE MILLING PROCESS. 

The soap, after it has been stripped and cut, is dried for 
about a day in bars, and then cut into thin, shavings by a ma- Chippin 

« • ■i • SOtip* 

chine called the “chipper,” such as illustrated on page 163. Only 
as much soap should be cut as can be used up in a day or two 
after drying, for it has been found that from shavings exposed 
to the air too long a time, the finished soap will have a less beau¬ 
tiful finish. The shavings are then spread out in layers to dry, 
and if possible are placed on sieves for this purpose, so as to dry 
as evenly as possible. The process may be conducted in a dry¬ 
ing room heated by steam, or simply by exposure to the air. In 
the latter case its duration is very indefinite, requiring, accord¬ 
ing to the weather, from 2 to 5 days, while in the former it may 
be finished in from 12 to 24 hours. 

The proper degree of drying is somewhat difficult to judge, Dr *’ ir) s- 
and it takes some experience to regulate it correctly. While in 
bars, a settled soap, made as described, will contain about 35% 
of water; for milling it has been found that about 18% of water 
is the best proportion, so that about one-half of the water pre¬ 
sent in the freshly cut shavings must be evaporated in drying, 
in order to obtain the best results. Insufficiently dried soap will 
be smeary and streaky, blisters readily and comes very easily 
and rapidly out of the plodder; in drying out afterwards some of 
the perfume will escape, along with the evaporating moisture; 
but if the drying be overdone the soap will be wanting in the 
necessary cohesion and will consequently be cracky as it comes 
from the plodder; the machine will work heavily, and only by 
heating the nozzle considerably can the soap be made to hold to¬ 
gether at all. Unevenly dried shavings will require more milling 
in order to make the mass homogeneous; if this is neglected the 
cakes will be of uneven density, will therefore not dissolve even¬ 
ly, and consequently show a ruffled surface and streaky appear¬ 
ance in use. The best and most reliable method of ascertaining 
the proper degree of drying consists in slightly overdrying the 
shavings at first, and then carefully adding the necessary amount 
of water as the soap may require. Some use shavings of fresh 
soap in place of water for this purpose. Additions of material 
other than soap proper, as talc, starch, and the like, will natur- 


g the 


308 


Milled Soaps. 


Perfuming a 
coloring. 


Milling. 


The plodder. 


ally modify the precise proportion of moisture required in the 
stock soap in order to have it of the proper consistency and 
texture. 

a Before adding- the color and perfume, the shaving's are passed 
once throug-h the mill, as the soap will pass better through the 
rollers—which must be set a little further apart this time on ac¬ 
count of the larg-er sized pieces—if there are no additions made 
at first which make the shaving’s slippery; besides the perfume 
and color are distributed more thoroug-hly in this manner. 

The soap, as it comes in thin ribbons from the mill, is run 
into a box which is lined either with zinc or lead, and the pre¬ 
viously calculated quantity of color and perfume is mixed in as 
well as possible. If insoluble colors are used they are conveni¬ 
ently tied up in a cloth of open texture which is then shaken 
from time to time over the soap as it comes from the mill. Some 
soap makers prefer to add the perfume after the color has already 
been well ground in, to save it from going- through the mill so 
often, as it is in this manner sufficiently well mixed with the soap 
with less opportunity to evaporate. 

The mass is now again ground in the mill, the rollers of 
which are set a little closer than they were the first time. This 
process of running the soap through the mill is repeated several 
times, according to the number of rollers on the machine and 
the condition of the soap, say about four times through a five- 
roller machine, until the mass is entirely homogeneous and free 
from streaks. The last time it comes from the rollers as thin as 
paper. 

With some practice the appearance of the soap as it conies 
from the mill can serve as a fair indication of its proper condition 
for the plodder; if too dry it has a strong lustre and little scales 
are apt to form here and there. If, while on the mill, it should 
be found that the soap is not dry enough after all, the proceed¬ 
ings must be stopped to permit further drying, unless some over- 
dried scraps are on hand to be milled in. 

From the mill the soap passes without loss of time into the 
hopper of the plodder. This machine feeds it automatically into 
a compartment where it is subjected to an enormous pressure, 
forming it again into a compact mass, and driving out all air 
bubbles. On the end of the machine opposite the hopper there 
is a nozzle into which a die of any desired shape is set, so that 
the soap is forced out through it in one continuous bar of any 


Milled Soaps. 


309 


desired form, so long- as the supply in the hopper is kept up; the 
shape of the nozzle used corresponds approximately to that of the 
cake to be pressed from it, a number of differently shaped nozzles 
being provided for the purpose. 

The end of this nozzle is kept warm, either by a direct flame 
or by a steam pipe placed around it, as the heat so applied makes 
the soap come out smooth and glossy. A good, pure soap, made 
mostly of tallow, will have a better finish with more heat at this 
part of the machine than one that is made of more cocoanut oil, 
and, perhaps, even containing filling. If too warm it will cause 
a streaky and rough finish if the soap is too soft, or blistered if 
too tough. The first few feet of the bar issuing from the plod¬ 
der must be returned to the hopper or mill, as they are not suf¬ 
ficiently compressed and would therefore be apt to crack after¬ 
wards, as is also the case if the soap shavings had been too dry. 

From the continuous working of the machine under high 
pressure the interior parts of the plodder may become heated, 
causing the soap to be blistered and otherwise unsatisfactory; 
some plodders have therefore been provided with a cold water 
jacket. However, as this operates on the soap in the first place, 
instead of on the heated parts of the machinery, it is better to 
stop work till the machine cools off. 

Sometimes, for some reason or other, the soap comes from 
the plodder wanting in the proper degree of pliancy. At such 
times the very careful addition of a little glycerin to the soap, 
on its last passage through the mill, may remedy the defect. 
Some cotton seed oil soap, added to it, may also be of benefit; or if 
the trouble arises from overdrying of the shavings, some water 
or shavings of fresh soap may be incorporated by thorough mill- 
in°\ Others again resort to the use of a few pounds of mineral 
soap stock, or melted bees’ wax, paraffine wax, or rosin soap. 
The addition of some (pure) gum tragacatith, which has pre¬ 
viously been made into a mucilaginous mass with water, is to be 
highly recommended in this connection, as it improves the lather 
and holds the soap together, preventing cracking. In like man¬ 
ner may be added 3-10% of pure wool fat or lanolin, if the soap 
is not to be of a pure white color, lanolin giving it a creamy tint; 
in this case the soap is dried more thoroughly before milling than 
when such an addition is not to be made. Should this addition 
make the soap streaky, it is necessary to previously rub up the 
wool fat with an equal amount of water. 


Heating the noz 
zle. 


Heating of plod¬ 
der. 


Remedying d e - 
feets in the soap 


310 


Milled Soaps. 


Pressing. 


New system ma¬ 
chinery. 


Difference in per¬ 
fuming various 
soaps. 


Quantity of per¬ 
fume used. 


Mixing of per- 
f u m e s before 
adding. 


A cutting machine with a single wire is placed so as to cut 
the continuous bar into convenient lengths, corresponding with 
the size of the cakes, and after a very short time for drying the 
soap is ready to be pressed. 

On pressing cakes of milled soap, its peculiar texture is made 
very prominent through the change in the shape of the bar, 
whereby the difference in the grain of the ends and the sides re¬ 
spectively—caused by the action of the machinery—is plainly 
shown by a mark. A machine has been patented for pressing 
cakes directly from the long bar, cutting off the soap required 
for a cake by the die, to obviate this mark. 

A system of milling soap as it comes from the kettle, with¬ 
out intermediate framing, has been briefly described in Chapter 
V, but as it is not as yetextensively used in this country, further 
details may be omitted. (See illustration opposite page 103.) 

PERFUMING MILLED SOAP. 

The subject of perfuming soaps in general will be treated 
hereafter in a special chapter (XVI), but a few remarks, which 
refer especially to the milled soaps in which the proper perfume 
is so important for their success, may find place here. 

The composition of the oils and tinctures when incorporated 
into an odorless, well-made soap by milling, retains its original 
odor unimpaired. In this respect there is a great difference be¬ 
tween milled and cold-made soaps, for, in the latter, the perfume 
undergoes a change,• no doubt induced in the course of the chem¬ 
ical reaction of the lye on the fat. A formula which gives a 
satisfactory and even elegant perfume for one, may therefore be 
far from making a pleasant odor for soap of the other process. 

It has further been demonstrated by practical experience 
that milled soap requires a larger quantity of perfume than does 
cold-made soap, in order to make the odor equally prominent; 
this is undoubtedly owing to its more intimate incorporation by 
milling, and is amply repaid by the increased durability of the 
odor. 

Instead of mixing the oils directly with the shavings, which 
causes a considerable loss by evaporation, the ingredients for the 
perfume may be mixed previously with a small amount of pure, 
odorless, white vaseline. Some manufacturers also use some orris 
root in the dark-colored milled soaps, one pound of which (for 
every 100 lbs. of soap) is made with the perfume and vaseline 


Miixkd Soaps. 


311 


into a dough-like mass and mixed with the shavings after they 
have passed through the mill once or twice, the idea being to add 
the perfume as late as consistent with thorough incorporation, 
so as to prevent evaporation of the costly ingredients as much as 
possible. 

Orris root and a carefully proportioned small quantity of 
liquid storax (either alone or melted together with the vaseline) 
make an excellent base for all perfumes in milled soap, making 
the odor more pronounced and more lasting. The same is true 
of the tinctures of benzoin, tolu, and civet. Tincture of musk 
also acts in the same manner, and where the price of the soap 
will permit it, should always be used for bringing out the per¬ 
fume, and for making it lasting. The tinctures named should 
be used in a somewhat more concentrated form than is usual when 
they are employed for handkerchief perfumes. 


Lasting qualities 
of perfume. 























' 


I 








- 




















































CHAPTER XVI. 


Coloring and Perfuming. 


At the present time, when so much weig-ht is placed on the 
outward appearance of the soap, few kinds are on the market 
which are not more or less eleg-antly perfumed—especially those 
intended for toilet purposes, which are in many cases also colored. 

An agreeable perfume is frequently taken by the consumer as 
proof of a superior article, even thoug-h, as a matter of fact, it 
sometimes is rather the means of hiding- a naturally disagree¬ 
able odor. Colors likewise can hardly be said to be of any actual, 
practical use, and in the case of a few may even be objectionable 
rather than otherwise. However, since the demand for a soap 
is g-enerally increased by the judicious use of suitable color and 
perfume, their employment has become nearly universal. 

COLORING. 

The manner of applying- the colors has already been de¬ 
scribed under the various processes of manufacture, so that only 
a few remarks about the colors themselves remain to be made. 

For the sake of the g-ood quality of the soap, if not for econ¬ 
omy, it is always advisable to use only the smallest amount of 
coloring- material that will g-ive the required shade, and to select 
the shade in harmony with the perfume and name of the soap. 

Thus a “Rose” soap is naturally colored red, “Lily” soap is left 
white, “Vanilla” soap should be brownish-yellow, and so forth. 

’ A . * . Division of colors. 

The colors used may be divided into two classes: those which 
may be added in solution (in water, lye, hot soap or alcohol), 
and those which form an insoluble and impalpable powder and 
are nearly all of mineral orig-in. Some aniline colors that are 




314 


Coloring and Perfuming. 


insoluble in alcohol, as well as in water and lye, dissolve readily 
in oil sassafras, or in a mixture of oil sassafrass, alcohol and glyce¬ 
rin. For transparent soaps the insoluble colors are of course unsuit¬ 
able. (Tampico yellow and Uranine are much used for them). 
Soluble colors, as a class, produce much handsomer effects than the 
insoluble ones,while the latter have the advantage of permanency 
which is lacking in most soluble colors. From another view colors 
maybe divided into perfectly harmless colors and those whose use 
although ordinarily also harmless, may under certain circum¬ 
stances—as when used by a person afflicted by some skin disease 
—give rise to unpleasant symptoms. The latter class is composed 
especially of those colors containing poisonous metals (mercury, 
lead, copper, arsenic), which are sometimes employed because 
they remain unaltered by time and exposure. Vermilion (red 
lead) and many kinds of aniline colors are of this class. It is 
also necessary to remember that many of the aniline colors are 
affected by alkali and therefore do not admit of use in such an 
article as soap. 

Natural color of Besides the colors added, we must mention the natural tints 

of soap made from certain stock, as reddish-brown from crude 
palm oil, yellow from rosin, greenish from hemp and olive oil, 
etc., and the brown color caused by the action of heat and lye 
on the sugar in transparent soap, and by impurities in crude 
potash. 

The special colors used for soap are of an enormous variety, 
and yet a few colors, used either singly or in combination with 
each other, are sufficient to make up the principal shades 
desired. 

White soaps are simply uncolored, but require great atten¬ 
tion and the most scrupulous cleanliness in their manufacture, 
as their white color is extremely delicate. When they have natur¬ 
ally a somewhat yellowish hue, the addition of a very small 
trace of blue (ultramarine) will change the shade to a light 
greenish, which is at all events preferable to yellow and less 
noticeable. (Ultramarine is used in the same manner by sugar 
refiners and others, to improve the appearance of their product.) 

Artificial colors Gray soap in all shades is made from white by the addition of 
and shades, varying quantities of black color, such as Ivory Black, nigro- 

sine, &c. 

Brown , in a great variety of shades, is produced by Sugar 
Color, Brown Ochre, Cutch, Chocolate, Umber, Burnt Sienna, 


Coloring and Perfuming. 


315 


Turmeric, Soudan brown, etc., and these may be all modified 
by the addition of yellow colors, producing - an immense variety. 

Yellow colors are also numerous, chief among - which are Saff¬ 
ron, Cadmium Yellow, Annatto, Picric Acid, Naphthaline Yel¬ 
low, Orang-e and Yellow Aniline; and for special shades also 
Turmeric and Bichromate of Potash. Sometimes crude palm 
oil is used in soap for the sake of its color and odor. Turmeric 
turns brown by the action of lye. Lemon Yellows, for transpar¬ 
ent soaps, are fluorescine and quinoline. 

Red is produced by Indian Red, Venetian Red, Aniline Red, 
Vermilion, Alkanet, Carmine, Bole, Colcothar, etc. 

Blue soap is now almost exclusively colored with Ultramarine 
in preference to Indigo, which was formerly much used. Ultra- 
marine is also used in combination for shades requiring - blue. 
Methylene blue is also much used. 

Green is produced by mixing - blue and yellow colors, as saff¬ 
ron or Chrome Yellow and Ultramarine; or Guinet’s Green is 
used, Chlorophyl, which however, fades on exposure. For soft 
soap the use of hempseed oil is sufficient to make the product 
green. Sligffitly bluish green are improved by the addition of 
some yellow color. 

Orange is made by mixing - yellow and red, or Mineral Orang-e 
is used as a color. 

Purple is a mixture of red and blue. 

Other shades in great number are produced by the aniline 
colors, such as Fuchsin, Eosin, Bismarck Brown, etc., and by mix¬ 
ing - several colors. 

For instance, Buff is produced from mixing - turmeric (1 part) 
and bichromate of potash (2 parts), dissolved in lye. 

Special Yellow tints are made by combinations such as: Yel¬ 
low Ochre 5 ounces, Burnt Sienna 10 drachms. Or: Yellow 
Ochre 1 ounce, Orang-e Mineral 1 ounce, Gambog-e 5 drachms. 

Still another shade is made of: Brown Ochre 1 ounce, Ver¬ 
milion 2L? drachms, Ivory Black ^ drachm. 

An olive color is made from green with a very little red. 

And thus the combination may be carried on without end. 

Some of these many coloring - matters, at least, deserve a few 
additional remarks: 

Cinnabar , a firy red color, is a compound of mercury and sul¬ 
phur (the sulphide of mercury) and insoluble; it has a hig-h 
specific gravity—a fact worth some attention when this color is 


316 


Coloring and Perfuming. 


used in cold-made soap. It is not infrequently adulterated with 
oxide of iron, plaster of Paris, &c. 

Chrome Red is a compound of chromium and lead, varying in 
shades according to the fineness of the powder. It is sometimes 
used in place of cinnabar, although its best shades are those of 
a powder almost too coarse for use in soap. 

Carmine is a more or less firy red powder, obtained from the 
Cochenille insect; soluble in ammonia. 

Chrome Yellow, chromate of lead; has a high specific gravity 
(a point to note in cold-made soaps); as this color sometimes 
causes black spots in the soaps, it is not so suitable as cadmium 
yellow which, however, is much more expensive. 

Cadmium Yellow is a compound of cadmium and sulphur and 
a very useful color, being absolutely permanent, though ex¬ 
pensive. 

Cur cumin, orange yellow crystals obtained from the curcumor 
root grown in East India, China, &c., soluble in alcohol and oils. 

Orlean Yellow , a product from the fruit of a South American 
tree; not readily soluble in water, more so in alcohol with which 
it forms a beautiful orange solution; with alkalies it gives a 
dark red. 

Saffron is a yellow color derived from flowers; it is very 
sensitive to light. 

Ultramar in, first found in a rare mineral (Lapis Lazuli), is 
now made from Kaolin by treatment with soda, sulphur, 
and carbon. It is unchanged by the action of air, light, and 
soap, and even improves by the exposure to air, but is very sen¬ 
sitive to acids. 

Berlin Blue , though used in perfumery, is destroyed by the 
action of soap. 

Indigo , a dry, vegetable product of dark blue to violet color; 
the powder is insoluble in water, alcohol, acids, and alkalies. 
It is rarely used now in soaps, being mostly superceded by ultra- 
marin, but a special compound of it, known as Indigo carmine, 
is used more often, especially to produce green colors in com¬ 
bination with some yellows. 

Guignefs Green is product of bichromate of potash and 
boracic acid. 

Ultramarin Green is an intermediate product of ultramarin 
blue manufacture. 

Chlorophyll is the green coloring matter of plants; it gives 


Coloring and Perfuming. 


317 


very beautiful shades of green and of course is not poisonous; 
very soluble in oils, but of little resistance to atmospheric in¬ 
fluences and light. 

Umber is a natural brown mineral color, found in many 
places, but especially near Siena (terra di Sienna) in Tuscany. 

Catechu , also called terra japonica, is not a mineral color as 
might be inferred from the latter name, but derived from the wood 
of a tree grown in Bengal; soluble in alcohol and hot water; 
dark red to brown. 

Gambir is almost the same as catechu. 

Tannic acid in watery solutions colors soap brown, darkening 
as the soap cools. It affords some desirable shades, but cannot 
be used in milled soaps. 

Sugar Color or Caramel can be used in milled soap, soluble 
in water. 

Coal Tar Colors. Of the extraordinary large number of coal 
tar colors a great many are unsuitable for soaps, either because 
they are decomposed by lye, or because they are insoluble in fats 
and soaps. Some can be made available by dissolving them with 
the addition of a small amount of alcohol, others by dissolving 
them in oleic acid (the acid reaction of which renders some basic 
colors soluble by forming salts of the oleic acid); turpentine 
also has a similar effect on some of these colors. Such colors 
prepared ready for use in soap are in the market in great num¬ 
ber. One of the earliest known aniline colors was Fuchsin, a 
very intense color of bluish red; other useful reds are Eosin, 
Erythrosin, Rhodamin, Bordeaux red, &c. The watery solution 
has a characteristic greenish efflorescence which, however, dis_ 
appears when used in soap. 

Among the yellow aniline colors those particularly worth 
mentioning are Uranin, Naphthaline, Chinolin, Resorcin yellow, 
Martinsyellow,&c. Picric acid which also belongs into this group, 
is too poisonous to be used for soaps. 

For blue soaps an aniline color known as Alkali Blue may 
be used; as it becomes lighter when exposed to lye, and darker 
when the lye becomes neutralized by the fat, the real color ap¬ 
pears only when the soap is finished, so that care is needed to 
prevent a darker shade than expected. Another blue is Methyl 
Blue which fairly withstands the action of light and affords 
some nice green shades when mixed with yellow. Still another 
useful preparation of this kind is Victoria Blue. 


318 


Coloring and Perfuming. 


Methyl violet, one of the most intense of all anilin colors is 
one much used for violet soap, as is also Indulin also an anilin 
color. 

Anilin greens are also numerous; among- them is Victoria 
green, but this as well as Naphtol green and the other greens are 
too sensitive to light, so that most green soaps are preferably 
colored by suitable mixtures of blue and yellow. 

Among the brown colors Bismarck Brown is the best known, 
there being but few anilin browns. 

As the anilin colors, as stated before, are not very soluble and 
such helps as alcohol, turpentine, &c., are not always desirable, 
there has sprung up an industry of making specially prepared 
soap colors which readily dissolve in oils and fats or even in 
slightly alkaline water. These colors come mostly in the form 
of amorphous powders and sometimes in the form of a paste. 
Their manufacture is in few hands who guard the same 
as trade secrets, and they are not equal in coloring power to or¬ 
dinary anilin colors. As these colors require various means of 
applying them, nothing can be said here on that point, the con¬ 
sumer being obliged to follow the directions furnished by the 
manufacturer with each kind of color. 

As regards their secret process, of manufacture, it is claim¬ 
ed by some who might be supposed to know, that in the case of 
some of these colors they are made very cheaply by suitably mix¬ 
ing those bought from the anilin color factories and “improving” 
them by the truly secret process of mixing in flour,starch or salt. 
Thus a beautiful red color of commerce is said to consist of 
rhodamin 1 part, starch 79 parts. 

The first anilin colors made were poisonous, but improve¬ 
ments made since were such that many of these colors are now used 
for articles of food even, so that with few exceptions there need 
no longer be any hesitancy in using them in soaps. It may also 
be mentioned that, since most of these products are very complex 
in composition, they have been given short trade names by which 
they are usually known and which we have used in the foregoing 
for that reason; thus a color ordinarily known as Soudan would, 
if called by its proper name, become: Anilin-azo-beta-naphthol; 
and Malachite green is “hydrochloric ether of tetramethyldia- 
midotriphenyl carbinol,” a name that ought to excuse almost 
anything. 


Coloring and Perfuming. 


319 


PERFUMING. 

The odorous substances are incorporated into the body of 
the soap either by milling- or by crutching- them in just previous 
to running- the soap into the frame. 

Many soaps, particularly the low-priced ones for the laundry, 
are perfumed simply by the incorporation of a single essential 
oil, so that in their case the perfuming- is an extremely simple mat¬ 
ter. Some importers of essential oils, as well as manufacturers 
of perfumery, also make a specialty of furnishing the soap manu¬ 
facturers ready-made mixtures of essential oils and other aro¬ 
matic substances, so that in the case of compounded perfumes, 
also, the soap maker need not necessarily trouble himself about 
the composition of perfumes. 

Nevertheless, there are some general rules applying to per¬ 
fuming soap which the manufacturer can not afford to be un¬ 
acquainted with, the more so since every soap maker will find it 
to be of advantage to collect at an early opportunity a good stock 
of experience in this branch of his business, even if he should 
find it more convenient for the time being to use only the ready¬ 
made mixtures. In making up a suitable combination of odor¬ 
ous substances the price is, of course, of the greatest importance 
to begin with. But a mixture of high-priced oils may be a very 
poor perfume, unless they are selected to harmonize with each 
other. To make up a suitable combination the odor which is to 
predominate is first selected and then compounded with such ad¬ 
ditions of other odors in suitable proportion as by experience is 
found to harmonize therewith. A small variation may mean a 
great deal practically in this respect. A very pleasant perfume, 
for instance, is made by 


Bergamot, 

6 parts, 

Rose geranium 

5 

Patchouli 

l}4 “ 

Santal, 

2 

Valeria, 



but, if the /aleria be increased to 2 parts, the mixture will be 
simply nauseating. 

Likewise, some oils are simply wasted by adding them to 
others which overpower them, or which form with them a mix¬ 
ture of an odor which is represented by some other, much cheaper 
oil, or quite insipid. Thus musk, which is very expensive, is 
practically killed by oil of fennel; otto of rose is overpowered 


Compounding 

perfume. 


Wasting oil by in¬ 
judicious mixing 


320 


Coloring and Perfuming. 


by oil of peppermint, etc. Lastly there are two very common 
sources of failure of even the best of formulas which it is im¬ 
portant to point out, namely: first , a soap which of itself has a 
disagreeable odor, and secondly the buying of oils not of the cha¬ 
racter and odor understood as the true properties of the oil nam¬ 
ed. A delicate odor is of course worse than wasted when incor¬ 
porated into a soap of fatty, rancid smell, and a formula cannot 
be a success when the oil used is not of the same character as 
that used in the original formula. 

The substances employed for obtaining the perfumes suit¬ 
able for soap are of several classes, namely: 

1. Vegetable substances , comprising essential oils, balsams, 
rosins, roots, and bark. The essential oils are by far the most 
commonly employed ingredients for this purpose; they are sub¬ 
ject to evaporation and deleterious changes on exposure to the 
light, air, or heat, as well as to rust in cans, dissolving lead from 
the latter, &c. They should therefore be kept in a cool, dark 
place, in glass vessels, and closely stoppered. 

Ready-mixed perfumes may be kept in a somewhat warmer 
place, as the elevated temperature accelerates the action of the 
oils on each other, whereby the perfume “ripens.” 

2. Animal substances, which comprise only a very small, but 
important number of raw materials for perfumery. They are 
generally used more because they serve excellently for fixing the 
more volatile vegetable odors than for the sake of their own 
odor. 

3. Artificial products, which are also not as yet very numer¬ 
ous, and mostly of rather recent origin. Some of these might 
also be classed with the vegetable substances mentioned above, 
from which they are extracted by more or less complicated che¬ 
mical treatment, while others are entirely artificial products. 

4. Pomades. The perfumed fat remaining when the princi¬ 
pal part of their odor has been extracted from the flower pom¬ 
ades of the perfumer, is used to a limited extent for perfuming 
soap, by adding this fat to other stock, in the manufacture of 
soap by the cold process. 

The following is an alphabetical list of the various substan¬ 
ces. (The plant from which the oils are derived are named in 
each case because in regard to some of the oils there is consider¬ 
able confusion and misunderstanding in the general literature): 
Allspice Oil, see Pimenta. 


321 


Coloring and Perfuming. 

Ambergris, a grayish white secretion of the Cachelot whale. 
Soluble in alcohol; has a pleasant musk-like odor if properly 
diluted. 

Ambrette Seed Oil, distilled from the seed of Abelmoschus 
Moschatus ; odor resembling musk and civet; Sp. gr. 0.900 to 
0.905; contains a free fatty acid which partly separates out at 
ordinary temperatures. A Copaiba oil mixture has been at 
times substituted for this oil. 

Anethol, an artificial product representing the essential 
constituent of oil of anise and possessing the odor of the latter; 
colorless. 

Anise Aldehyde or Aubepine; a colorless liquid resembling 
in odor the blooming Hawthorn; must be kept in well-stoppered 
and well-filled bottles, as it oxidizes readily if exposed to the air; 
agrees well with orange oil and oils of similar odor; readily sol¬ 
uble in alcohol. 

Anise Oil; made from the seeds of Pimpinella Anisum\ should 
be colorless or faintly yellow. Below about 60° F. it solidifies 
to a white, crystalline mass. (Should not be confounded with 
oil of Star anise, made of the fruit of Illicium Anisatum .) It 
must be used sparingly, as its penetrating odor easily overcomes 
that of other oils used. Sp. gr. 0.980 to 0.990 at 17° C.; optical 
rotation to the left (very slight); consists chiefly (90%) of ane¬ 
thol; has been extensively adulterated with the stearopten ob¬ 
tained from oil of fennel, which, however, can usually be de¬ 
tected by the change thereby caused in the optical rotation of the 
oil. Anise oil congeals between 60 and 66° F. 

Artificial Oil Sassafras is a production closely related to 
Safrol. 

Artificial Oil Wintergreen (Methyl Salicylate) is a col¬ 
orless or yellowish liquid; sp. gr. 1.183 to 187; optically inactive; 
manufactured on a large scale and used extensively to supplant 
the Natural Oils of Wintergreen and of Sweet Birch. To test 
these latter two oils, as well as the artificial (synthetic) oil for 
adulteration with other volatile oils or with petroleum, add to a 
measured quantity of the sample in a test tube ten times its vol¬ 
ume of a 5% solution of pure caustic soda, shake well till a con¬ 
siderable white precipitate is produced; plug the tube loosely, 
place in boiling water for five minutes, shaking occasionally; the 
precipitate should dissolve and form a perfectly clear, almost 


322 


Coloring and Perfuming. 


colorless solution, and no oily drops should separate on the sur¬ 
face nor at the bottom. 

Aubepine: See Anise Aldehyde. 

Balsams: See under Copaiba, Peru, Storax, Tolu. 

Bay Oil. This name is given to two different oils: One, 
also called “Sweet Bay,” from Laurus Nolnlis , is used in soap to 
a small extent; the other, also known as “West Indian Bay Oil,” 
is distilled from the leaves of Myrcia Acris , and used in the man¬ 
ufacture of bay rum and of soap, especially bath and shaving 
soaps; the oil of Myrcia is a yellow to brownish-yellow liquid 
whose odor reminds one of clove oil; sp. gr. 0.970 to 0.990; gives 
sometimes a clear, sometimes a somewhat turbid solution with 
90% alcohol. 

Benzoin, a gum rosin, with a vanilla-like odor, from the 
Styrax Benzoin ; collected in a manner similar to that of pine rosin. 
That from Siam has the finest odor; Sumatra benzoin resembles 
Styrax somewhat in odor. 

Bergamot Oil, expressed from the rind of the fruit of Citrus 
Bergamia. Pale yellow to greenish. Must be carefully kept from 
the air, as it is very prone to absorb oxygen and become turpen¬ 
tine-like in odor. It differs from other oils of this family of 
plants in that it forms a clear solution with caustic potash lye. 
Sp. gr. 0.882 to 0.886; optical rotation 9 to 15 to the right in a 
100 mm. tube. At 70 F. it should give a clear solution with 
1)4 to 2 volumes of alcohol of 80% b} T volume; sometimes a pure 
oil does not answer to this test, in which case, to prove absence 
of fatty oils, on evaporating a small sample over a water bath 

until all odor has disappeared, the remaining soft residue should 

• 

not exceed six per cent; a greater residue tending to show the 
proportionate presence of fatty oils. The value of this oil 
(like that of several other oils) depends principally on one of 
its constituents, i. e. about 35% to 40% of linaloyl acetate. Its 
principal adulterants are turpentine, oil of lemon, oil of orange, 
all of which decrease the specific gravity; the latter is increased 
by adulteration with fatty oils, cedar-wood oil, gurjun-balsam 
oil. 

Birch Oil, also called oil of Sweet Birch, is distilled from 
the bark of Betula Lenta , Sweet Birch or Black Birch. It is colorless 
or yellowish, and its odor and taste are very similar to those of 
wintergreen for which indeed the oil is largely sold. Sp. gr. 1.180 
to 1.185; optically inactive; almost a pure methyl salicylate (of 


Coloring and Perfuming. 


323 


which the artificial or synthetic oil of wintergreen consists). 
Has been found adulterated with petroleum, &c. See tests under 
“Artificial Oil Wintergreen.” 

Bitter Almond Oil, obtained from Amygdala Amara , the 
bitter almond, by macerating with water and then distilling, 
but also made largely from peach and apricot kernels. Colorless 
or yellowish. Must be kept in air tight container, as on expos¬ 
ure to air the oil, (especially that freed from prussic acid) will 
change to a white, odorless, worthless mass (benzoic acid). If 
oil from a partly used bottle must necessarily be kept on hand, 
it should either be transferred into a bottle of smaller size so as 
to exclude the air again on securely corking it, or there should 
be added to the partly emptied bottle alcohol in the proportion of 
10% of the oil still remaining; less than 10% of alcohol, how¬ 
ever, have no preservative effect whatever. Of course 10% more 
of this mixture must then be used in the soap, &c., than if the 
pure oil were used from a fresh bottle. Seealso “Mirbane,” un¬ 
der Artificial Products. 

Bitter Almond oil has a sp. gr. of 1.050 to 1.060 and is opti¬ 
cally inactive; it consists of benzaldehyde (which on exposure to 
air oxidizes to benzoic acid) and 2 to 4% of hydrocyanic acid, 
and is therefore highly poisonous, even the oil freed from hydro¬ 
cyanic acid being* not free from dangerous effects. Oil of higher 
sp. gr. than named above is likely to contain much more of the 
poison, as high as 11% having been found in some specimens 
whose sp. gr. was above 1.090. 

The artificial oil has been frequently used as an adulterant, 
and even in some cases to entirely substitute the natural oil. Al¬ 
cohol and oil of turpentine are also frequent adulterants, but 
lower the specific gravity. There is as yet no chemical test that 
will disclose adulteration with pure benzaldehyde. For the detec¬ 
tion of artificial oil containing chlorinated products the following 
has been devised by an American firm: A piece of strong, clean cop¬ 
per wire, with a looped end, is held in a non-luminous flame, such 
as that of the ordinary Bunsen burner or alcohol lamp, until no 
color is imparted to the flame, and then permitted to cool. A 
drop or two of the oil to be tested is then allowed to fall on the 
looped end of the wire, avoiding any contact of the latter with 
the fingers, and the oil subsequently ignited and left to burn 
outside of the flame. The looped end of the wire is now slowly 
brought in contact with the lower outer edge of the flame. If 


324 


Coloring and Perfuming. 


the oil is artificial it will at once impart a distinct but quite tran¬ 
sient green tinge to the flame, caused by the vapor of the chlor¬ 
ide of copper formed, while a pure natural oil will produce at 
the most but a slight yellow color. 

Cananga Oil. See also under Ylang-Ylang. Sp. gr. 0.915. 
Soluble in 1 to 2 volumes of 90% alcohol. Often adulterated 
(with cocoanut oil, &c.) Should remain liquid at freezing- tem¬ 
perature. 

Caraway Seed Oil, distilled from seeds of Carurn Carvr, 
colorless to light yellow; aromatic odor; turns yellow to brown 
by age. 

Sp. gr. 0.905 to 0.920. Contains limonene (formerly called 
carvene) and carvol. Optical rotation 75 to 85- to the right in 
a 100 mm. tube. 

Caraway Chaff Oil has a less agreeable odor than that 
from the seed. 

Cassia Oil, from the leaves and leaf stems of Cinnamomum 
Cassia , growing in China. Yellow, gradually becoming dark 
reddish-brown and thickly fluid. It is similar to, but not as fine, 
as Cinnamon Oil. As it makes the soap yellowish it should not 
be used in white soaps. 

Sp. gr. 1.055 to 1.065. Consists chiefly of cinnamic alde¬ 
hyde (75 to 88%), on which its value depends chiefly and which 
should therefore be at least 80%, although oil of this strength is 
frequently not on the market at all. Has often been found adul¬ 
terated with rosin, fatty oils, petroleum, cedarwood oil, alcohol, 
&c. Genuine oil may, however, be as low as 50% in aldehyde, 
but is then less valuable in proportion than the oil having a high¬ 
er percentage. A synthetic cassia oil (cinnamic aldehyde) has 
also been brought upon the market, which is said to be prefer¬ 
able, among other reasons on account of its lighter color. 

Cassie Oil. Under this name an oil is brought into 
commerce which is made from the black currant (Ribes Niger), 
but the real cassie perfume is from a flower. Acacia Farnesiana , 
the essential oil of which, however, is not an article of commerce. 
These oils are not to be confounded with cassia oil. 

Cedar Wood Oil, distilled from wood of Juniper us Virginia na 
(largely from the saw dust of lead pencil factories); yellowish 
to greenish-yellow, thickly fluid; sp. gr. 0.940 to 0.960. Another 
kind, from the wood of Cedrus Libani, is brownish-yellow and has 


Coloring and Perfuming. 


325 


a sp. gr. of 0.985 and a somewhat different odor. Cedar wood 
oil improves during storage for about a year or two. 

Cinnamon Oil, from bark of Cinnamomum Zevlanicum . Pale 
yellow; often adulterated with oil of cassia. Sp. gr. 1.025 to 
1.035. Consists chiefly of cinnamic aldehyde and some eugenol. 
Has been found adulterated with artificial cinnamic aldehyde 
which, if free from chlorine, is impossible to detect by any means 
at present known. 

Citron Oil, from Citrus Mcdica. Very similar to the oil of 
lemon, which is generally substituted for it. 

Citronella Oil; one of the grass oils, distilled from the 
Andropagon Nardu-s , growing in Ceylon and about Singapore; 
similar in odor to that of the oil of Verbena and of the Indian 
Lemon Grass Oil, in place of which it is sometimes used. It varies 
from colorless to a greenish-yellow to a brown color. 

Sp. gr. 0.895 to 0.915 (Rectified oil as low as 0.890). Fre¬ 
quently adulterated at its place of manufacture (India) or after¬ 
wards, with fatty oils or petroleum. To detect these, thoroughly 
shake a carefully measured sample of the oil with ten times its 
volume of alcohol of 80 per cent strength (sp. gr. 0.8645); this 
is best done in corked test tube of convenient size; then let it rest 
for 12 hours or longer; if neither fatty oils nor petroleum are 
present, the solution will be clear or at least only slightly opa¬ 
lescent, and no oil drops will separate from it, neither above nor 
at the bottom of the test tube. 

Large amounts of this oil are used in the manufacture of 
Geraniol. 

Civet, obtained from an animal related to the cat and found 
in Africa. It is a soft, smeary, white (later brownish) mass; its 
odor is somewhat like that of musk and ambergris. 

Clove Oil, distilled from the unexpanded flowers of Eugenia 
Aromatica. Colorless and thin when fresh, but soon becomes yel¬ 
low and thickens on exposure to air. Should not be used in cold- 
made soap, except in small amounts. Sp. gr. 1.050 to 1.070. 
Contains 80-90% eugenol. If the oil is free from adulteration 
with petroleum, oil of turpentine, and fatty oils, it forms a clear 
solution with double its own volume of a mixture of 2 volumes 
of alcohol and 1 volume of water. The oil of Clove stems is of 
a less fine odor. The oil of cloves and of clove-stalks furnish 
the Eugenol of commerce 

Copaiba Balsam. A yellowish-brown syrupy liquid, from 


326 


Coloring and Perfuming. 


several varities of Copaife?'a. The best is that known as Brazil 
Balsam, which has an odor not unlike that of santal wood oil. 

Coumarin is the odorous principle of the tonca bean, just as 
vanillin is of the vanilla bean, and is manufactured artificially, 
in the form of crystals both from the bean and also from leaves 
of a so-called “vanilla plant,” as well as synthetically. It is 
soluble in water, alcohol, glycerin, ’vaseline, and in oils; used as 
a fixing agent for the perfumes used in soap and for the purpose 
of assisting in blending the odors of the various oils, &c. used. 
Its odor is that of new mown hay and agrees well with lavender, 
geranium, &c. Has been found on the market adulterated with 
antifebrin. 

Dill Oil, distilled from fruit of A net hum Graveolens. Pale 
yellow, characteristic odor, sp. gr. 0.905 to 0.915. The East 
Indian dill oil has a markedly different odor. 

Eucalyptus Oil is distilled from the fresh leaves of Eucaly¬ 
ptus globulus and a number of other species of Eucalyptus; 
the oils from these different sources vary more or less from each 
other in composition, and therefore also in odor, specific gravity, 
opticial rotation, &c. Those from Eucalyptus globulus, E. oleosa, 
and some others, have strongly antiseptic properties, owing to 
more or less cineol (eucalyptol) being contained in them, and are 
therefore also used medicinally in asthmatic and bronchial 

affections. 

Eugenol occupies a similar position to oil of cloves as Saf- 
rol does to oil of Sassafras; sp. gr. 1.070; gives a clear solution 
in a 1 or 2% solution of caustic potash. 

Fennel Oil, distilled from fruit of Foeniculum Vulgare; almost 
colorless and of a sweetish odor. Sp. gr. 0.960 to 0.975. Con¬ 
tains about 60% of anethol (which is also the principal constit¬ 
uent of anise oil) besides pinene, phellandrene, &c. As much 
oil appears on the market that has been deprived of a portion of 
of its valuable constituents, it may be observed that a genuine 
fennel oil solidifies at a temperature of 3 C., owing to the 

anethol contained in it. 

Gaultheria, see Wintergreen. 

Geraniol. A colorless liquid of rose like odor; should give 
a perfectly clear solution with 15 times its volume of 50% alco¬ 
hol; must be kept in a cool place, in completely filled, well- 
stoppered bottles; sp. gr. 0.880 to 0.885. A similar, or possibly 
chemically identical body is Rhodinol. 


Coloring and Perfuming. 


327 


, Geranium Oie, from herb of several species of Pelargonium , 
as P. Roseum and others; also called Oie of Rose Geranium, and 
closely resembling- in odor the oil of Rose which is often adulter¬ 
ated with it. (The names “oil of rose geranium” and i‘Turkish 
oil of g-eranium” and “East Indian oil of geranium” are some¬ 
times falsely applied to the oils of gingergrass and of palma- 
rosa q.v.) 

Geranium oil appearson the market as “Algerian,” “French,” 
“Reunion,” and “Spanish,” geranium oils, resembling each other 
fairly closely in specific gravity (0.886 to 0.898) and opticial ro¬ 
tation (—7° to —11°); their chief constituent is geraniol, of 
which the oil contains 80 to 8 5%. If they form a perfectly clear 
solution with 2 to 3 times their own own volume of 70% alcohol, 
they are free from adulteration with fatty oils, petroleum and 
oil of turpentine. The oil is affected by a peculiar odor if it is 
long kept in tins and should therefore be refilled into glass re¬ 
ceptacles at the earliest opportunity. 

Ginger Grass Oil is probably from the same grass from 
which Palmarosa oil is obtained, but of inferior quality and 
often heavily adulterated with fatty oils, &c. 

Guaiacum Wood Oie, distilled from a South American wood 
of uncertain botanical origin; but probably Bulnesia Sarmienti 
Eor., of the Argentine Republic. Very thick and viscid, violet¬ 
like odor; which in soaps resembles the odor of tea, has been sold 
as “champaca oil” which is not a commercial article at present. 

Heeiotropin (Piperonal) is a chemical product (in the form 
of crystals) related to Coumarin and Vanillin, and is much used 
in soap to imitate the odor of the heliotrope, which it resembles very 
closely. It is readily soluble in alcohol, glycerin, vaseline, and 
in essential oils. A slight addition of Coumarin to it improves 
and strengthens its odor; the oil of petitgrain, lavender, geran¬ 
ium, lemon, and bergamot and also aubepine harmonise well 
with it. It must be kept in a cool , dark place, and should be dis¬ 
solved in alcohol before it is added to the soap to prevent spots. 

Ionone, made by condensation of citral and acetone and 
subsequent treatment with dilute sulphuric acid; when properly 
diluted it has the characteristic odor of violets and may be ad¬ 
vantageously combined with orris oil; not affected by free alkali. 

Kuro-moji Oie, distilled from a wood (. Linderci Sericea ) in 
Japan; balsamic odor; sp. gr. 0.890. 

Lavender Oie, distilled from flowers of Lavandula Vera . 


328 


Coloring and Perfuming. 


Colorless to light yellow; very sensitive to light and air. The 
true lavender oil must not be mistaken for the oil of Spike Laven¬ 
der distilled from the herb of Lavandula spica which has a similar 
but less agreeable odor. The best varieties are the English and 
the Mount Blanc oils of Lavender, of which, however, each has 
a distinctive odor. 

The oil of lavender flowers has a specific gravity of 0.883 
to 0.895 and an optical rotation of —5° to —8 in 100 mm. 
tube; it contains linalool, linaloyl acetate and geraniol, besides 
a very little cineol (which is much more abundant in oil of 
spike lavender). It should contain about 35% linalyl acetate* 
its most valuable constituent, and, to prove its purity, should 
form a clear solution with 3 volumes of 70% alcohol. The oil 
of Spike Lavender is much less fragrant than the foregoing, the 
odor somewhat resembling rosemary, owing to a different com¬ 
position; sp. gr. 0.905 to 0.920; optical rotation +1 to +9°; it 
should form a perfectly clear solution with three times its volume 
of 70% alcohol, if thoroughly shaken and kept in a temperature 
of 70° F.; if it does not it is probably adulterated with oil of tur¬ 
pentine or oil of cedarwood. Spike oil is a common adulterant 
of lavender oil, but manifests its presence by increasing the spe¬ 
cific gravity of true lavender oil; cedar-wood oil also increases 
the specific gravity; alcohol and turpentine lower it, so that the 
simultaneous presence of alcohol and spike lavender oil might 
counterbalance each other and hence not be indicated by che spe- 
fic gravity. 

Lemon OrL, expressed from the fresh peel of the fruit of 
Citrus Limonum . Pale yellow; loses its odor rapidly on exposure 
to light and air, being one of the most readily deteriorating es¬ 
sential oils. Often adulterated with turpentine and acquiring 
the odor of the latter on exposure to air; should be kept in com¬ 
pletely full bottles, and preferably in a dark, cool place. Its value 
depends almost entirely on the constituent “citral.” Sp. gr. 


*Tliis requirement, it is but fair to say, is one demanded by some aut¬ 
horities, while others maintain with equal positiveness, that the percentage 
of linalyl acetate in the finest of oils is much below the amount stated; 
(which is certainly true of English oils) that the most valuable principles 
of the oil have not yet been determined; and that the strength of a sample 
cannot yet be determined by chemical means. Whatever the true solution 
of the question may be, the nose is in this instance again one of the most 
reliable guides. 



Coloring and Perfuming. 329 

0.857 to 0.860; optical rotation +60° to +64° in a 100 mm. 
tube. The examination of specific gravity and of optical rota¬ 
tion are among-the most reliable tests for this oil, the determina¬ 
tion of citral being- a complicated process. In the manufacture 
of “concentrated” oil of lemon terpene is separated from the oil 
and used ag-ain, on the other hand, to adulterate ordinary oil of 
lemon; this is a refinement of the former turpentine adulteration 
for which as yet no reliable test is known. So also is the opti¬ 
cal rotation no long-er reliable by itself, as adulteration with a 
mixture of oil of orang-e and oil of turpentine in certain propor¬ 
tions does not chang-e the optical rotation. 

Lemon Grass Oil, distilled in the East Indies from Andro - 
pogon Citratus ; resembles in odor the oils of lemon, citronella, and 
of verbena, and sometimes called “East Indian oil of Verbena;” 
sometimes also known as “oil of Melissa,” a name which proper¬ 
ly belong-s, however, to the oil derived from Melissa Officinalis 
which has a much finer odor. Yellowish to yellowish brown; 
sp. gr. 0.895 to 0.905; should form a clear solution with double 
its volume of 70% alcohol; frequently adulterated, and in turn 
used to adulterate the oil of verbena; larg-ely used for the manu¬ 
facture of citral and then sometimes broug-ht upon the market 
with part of its citral removed. 

Lilacine. See Terpineol. 

Lime Oil, expressed from rind of fruit of Citrus Limetta ; sp. 
gr. 0.880. Oil obtained by distillation has a less agreeable odor. 
The oil made from the West Indian lime, Citrus Medica , resem¬ 
bles lemon oil in odor but is strong-er, while the first named va¬ 
riety has an odor resembling- berg-amot rather than lemon; the 
sp. gr. of the West Indian oil is 0.880 to 0.885. 

Linaloe Oil. Distilled by Mexican Indians from a wood 
(probably that of the white cedar); its odor is somewhat sugges¬ 
tive of the rose; colorless; sp. gr. 0.875 to 0.885; contains linalool 
and a little g-eraniol; one part of this oil should g-ive a clear 
solution with two parts of 70 per cent alcohol. Has been found 
adulterated with fatty oils. See also Linaool. 

Linalool: A colorless liquid; sp. gr. 0.880; optical rotation 
_|—2°; forms a perfectly clear solution with two volumes of 70 
per cent alcohol; the essential constituent of oil of linaloe. 

Mace Oil, distilled from the flesh enveloping- the nutmeg-, 
Myristica Fragrans, also from the nut itself. Colorless to yellow¬ 
ish-red. This oil must not be confounded with fatty oil of mace. 


330 


Coloring and Perfuming. 


Sp. gr. 0.910 to 0.930; soluble in 3 times its volume of 90 per 
cent alcohol. 

Marjoram Oil, Sweet. Distilled from herb of Origanum 
Majoramr, yellowish or greenish yellow; sp. gr. 0.890 to 0.900. 
For Wild Marjoram see Origanum. 

Meeissa Oil, from herb of Melissa Officinalis. Is not used 
very much, being quite expensive and in fact hardly a com¬ 
mercial oil. But the name is sometimes used to designate oil 
of Lemongrass, and the oil is therefore also called “citron- 
melissa.” 

Mirbane, also called, “Nitro-Benzole,” “Oil of Mirbane,” 
“Artifical oil of Bitter Almonds,” and “Essence of Mirbane.” 
It is made of benzole (a coal tar distillate), by treating it with 
fuming nitric acid and sulphuric acid. It resembles the 
oil of Bitter Almonds in odor, but is very poisonous and explo¬ 
sive, and should therefore not be used for flavoring purposes, 
and be handled more carefully than is usual. (The name “Arti¬ 
ficial Oil of Bitter Almonds” is also given to another product, 
Benzaldehyde, which is also a substitute for the natural oil soaps 
sometimes unknown to the buyer, and non-poisonous.) Mirbane 
turns the soap yellow on exposure to light and sun, and such soaps 
therefore require to be well packed. It is claimed, however, that 
the best qualities of the oil do not do this. Sp. gr. 1.200. 

Musk has the most agreeable odor of the animal substances 
used in perfumery. It is derived from a deer, living on the plat¬ 
eaus of the Himalayas, which secretes it in a small sack on the hind 
part of the belly. It occurs in commerce as “musk in pods,” and 
as “grain musk.” It is used in extremely great dilution for the 
finest soaps, either for the sake of its own odor or because it 
serves so well to fix other odors. The grains should have a fatty, 
shining appearance and brownish black color; if they look dry 
and dull, a previous extraction of alcohol is to be suspected. It 
is frequently adulterated with dried blood, partly burnt meat, 
etc. By burning a small piece in an alcohol flame the odor of 
burning flesh reveals the latter sophistication. The best musk 
is that from Tonquin, which is often adulterated, however, by 
Assam musk which has a weaker odor. The Roentgen rays 
have been successfully employed for detecting pieces of lead in 
unopened musk pods, lead being a frequent adulterant of the 
latter. 

Myrcia, See Bay Oil. 


Coloring and Perfuming. 


331 


Nkroli, See under Orange. 

Nerofin: Crystals representing 1 the odor of oil Neroli; sol¬ 
uble in alcohol, fatty oils and essential oils; more lasting in odor 
than oil Neroli and of about the same strength. 

Nutmeg Oil, from the fruit of the same plant which also 
furnishes the oil of Mace which it closely resembles. Colorless 
or pale yellow; darkening with age; sp. gr. 0.870 to 0.915. 

Oenanthic Ether, (Artificial Cognac Oil), a colorless, oily 
liquid, giving a fruity aroma to soaps, especially when used with 
a little Peru balsam and the oils of cassia and lavender. 

Oeibanum Oil, distilled from a gum rosin of that name; col¬ 
orless; balsamic odor; sp. gr. 0.875 to 0.885. 

Opopanax Oil, distilled from a gum rosin of the same name; 
greenish-yellow; balsamic odor; sp. gr. 0.860 to 0.900. Easily 
rosinifies on exposure to air. 

Orange Oil is of two principal kinds: From the peel of the 
bitter orange is expressed the oil of Orange Bigaradl; from 
that of the sweet orange the Oil of Portugal; if simply oil 
of orange is called for, the oil of bitter orange is generally meant. 
The oil made from the flowers of the true bitter orange is called 
Neroli Bigarade; if only the petals of the flowers are used it is 
called Neroli Petale. The flowers of the sweet orange furnish 
the oil Neroli Portugal. The oil distilled from the leaves and 
unripe fruit of the orange tree is called oil Petit Grains. The re¬ 
marks concerning the keeping of lemon oil apply also to these 
oils. 

The oil distilled from the flowers of the bitter orange (oil of 
Neroli) is yellowish to almost brown; sp. gr. 0.875 to 0.888; op¬ 
tical rotation-f-5° to-(-10 o in a tube of 100 mm. The oil expressed 
from the peel of either the bitter or the sweet orange is yellow¬ 
ish; sp. gr. of both kinds 0.848 to 0.854, and optical rotation-j- 
96° to+99° in a 100 mm. tube. The examinations of specific gravity 
and of optical rotation are, as in the case of lemon oil, the most 
important tests for orange oils and indeed more reliable for or¬ 
ange than for lemon oil as it is difficult to find an adulterant for 
the former that will not effect its rotatory power. Petit Grain oil 
is less fine than oil neroli; sp. gr. 0.890 to 0.900; soluble in twice 
its volume of 80 per cent alcohol. 

Origanum Oil is generally a misnomer for Oil of Thyme. 
Properly the name belongs to the oil of Wild Marjoram; sp. gr. 
0.895. 


332 


Coloring and Perfuming. 


Orris Root, from Iridis Florentine; much used for violet 
soap. (See also remarks on it in the chapter on milled soap.) 

Orris Root Oil. Distilled from the rhizomes of several 
species of Iris; solid at ordinary temperatures; violet-like odor. 

Palmarosa Oil is distilled in India from the grass of a species 
of Andropogon , but notwithstanding this it is frequently spoken 
of as “Turkish Geranium Oil” and as “East Indian Geranium 
Oil.” It is colorless to pale yellowish and of an agreeable odor; 
sp. gr. 0.890 to 0.900. Soluble, if pure, (like the oil of geranium) 
in 2 or 3 volumes of 70 per cent alcohol. Frequently adulterat¬ 
ed with fatty oils. 

Patchouly Oil, distilled from the leaves of Pogostemon 
Patchouli yellowish-green to dark brown, ill-smelling till highly 
diluted; serves as a basis for, and partly to fix, other perfumes, 
and must be used very sparingly. Sp. gr. 0.970 to 0.990; adult¬ 
erated with cedarwood oil. This oil improves in quality for 
several years if stored properly in glass bottles, (not in tins). 

Pennyroyal Oil, European, (French). This oil is distilled 
from the herb of Mentha Pulegium and should not be mistaken for 
the American Oil of Pennyroyal (from Hedeoma pulegioides ) 
which is different in odor, &c. Yellowish in color; mint-like 
odor; sp. gr. 0.935 to 0.955; optical rotation in a 100 mm. tube + 
18° to +23'. Among the best tests for its purity is its property 
of giving a clear solution with twice its volume of alcohol of 70 
per cent by volume. 

Peppermint Oil is distilled from the herb of Mentha Piperita; 
colorless to pale yellowish-green. This oil, from its cooling after¬ 
effect, is much used—like the oil of wintergreen—for perfum¬ 
ing tooth soaps and similar preparations. Sp. gr. 0.900 to 0.925. 
The essential constituent of this oil is menthol, the value of a 
given sample being ascertained by finding the proportion of men¬ 
thol present; a fair sample of peppermint contains about 50 per 
cent of total menthol; the Japanese oil naturally contains about 
75 per cent, but its less agreeable taste depreciates its otherwise 
greater value for such purposes as tooth soaps, &c. The estima¬ 
tion of the menthol present is so much more important as oils 
have been on the market from which a part of the menthol had been 
abstracted. When an American oil which is normal as to men¬ 
thol contents is thoroughly cooled in a freezing mixture of ice 
and salt, and a few menthol crystals are then added, the sample 
soon after congeals to a solid mass; Japanese oil is very frequent- 


Coloring and Perfuming. 


333 


ly deprived of its menthol in the manufacture of the latter arti¬ 
cle; with English oil this is not the case, this oil being more 
costly than menthol itself. Adulteration by turpentine is detect¬ 
ed by decreased specific gravity. The principal varieties of this 
oil are the American, the English, and the Japanese, differing 
markedly in odor, taste, and physical properties. 

Peru Balsam, from Toluifera Pereira; used to fix other odors. 
With a vAnilla or benzoin-like odor. As its odor is changed by 
the action of lye, it is out of place in a cold-made soap. An oil 
distilled from it is also used in perfumery. 

Pimenta Oil, also called Oil of Allspice; distilled from 
fruit of Pimenta Officinalis. Colorless to pale yellow; odor and 
composition resembling those of clove oil; sp. gr. 1.045 to 1.055. 
To show absence of petroleum, turpentine, and fatty oils, one 
volume of oil of pimenta should form a clear solution with two 
volumes of a mixture composed of alcohol 2 volumes and water 1 
volume. 

Pine Needle Oil. From the leaves of several species of 
pine oils are distilled which differ somewhat in odor, &c.; some 
of these are used to a small extent in perfumery, and more large¬ 
ly medicinally; a Siberian pine-needle oil is much used for per¬ 
fuming soaps. Turpentine oil perfumed with acetic acid has been 
sold for genuine “pine oil.” 

Rhodinol: See Geraniol. 

Rhodium, See Rosewood. 

Rose Geranium, See Geranium. 

Rose Oil, Attar of Rose, Otto of Rose, are names of the 
oil derived from several species of roses, Rosa Damascenns , &c. 
The oil varies from a liquid consistencv to that of butter; yellow 
or greenish in color; almost solid at about 60 F; sp. gr. 0.860 to 
0.875 at 70° F. Said to be rarely unadulterated when it leaves 
the principal place of production (Bulgaria), the most usual 
adulteration being geranium, lemongrass and gingergrass oil. 
When congealed the oil presents scale-like, odorless crystals of 
stearopten contained in a matrix of a more easily liquefied, frag¬ 
rant portion called by some rhodinol, but by others geraniol, 
admixed with a very small portion of some other fragrant sub¬ 
stances. As yet no reliable tests for the purity of this oil have 
been discovered, and the odor is still the principal guide in judg¬ 
ing a sample. 

Rosemary Oil, from the leaves of Rosmarinus Officinalis. 


334 


Coloring and Perfuming. 


Colorless to pale yellow or green; penetrating, somewhat cam¬ 
phor-like odor. Sp. gr. 0.895 to 0.915. One part of the oil 
should form a clear solution with ^ to 1^ volumes of alcohol 
of 90 percent by volume, at 70° F. Optical rotation to the right. 
Frequently heavily adulterated with oil of turpentine and 
camphor. 

Rose Wood Oil; the true oil of this name is not a commer¬ 
cial article; what is sold as such or as “Oil of Rhodium” is said 
to be a mixture of rose oil with other essential oils. 

Rue Oil, distilled from leaves of Rata Graveolens. Yellowish 
color; sp. gr. 0.834 to 0.840. Often adulterated with alcohol, 
turpentine, petroleum, &c. Pure oil gives a clear solution with 
two to three times its volume of alcohol; the presence of turpen¬ 
tine or petroleum cause a turbid solution. 

Safrol, is a colorless liquid product obtained by the frac¬ 
tional distillation of oil of Japanese Camphor, it is an antiseptic 
and identical with the principal constituent of oil of Sassafras, 
for which it is now largely substituted in household and cold-made 
soaps. Sp. gr. 1.100 to 1.108. It is either mixed with the soap, 
or, in cold-made soap, with the fats before adding lye. It is used 
either alone or mixed with oil of Citronella, to which a little oil 
of Cedarwood may be added to make it more lasting. This com¬ 
position is one of the cheapest perfumes for soap that can be 
had. Other good combinations are those with Cassia, Lavender, 
Rosemary, and Spike. 

Sage Oil, from leaves of Salvia Officinalis ; not unlike pepper¬ 
mint, but less strong; imparts coolness to the mouth, and is there¬ 
fore sometimes used for mouth washes. Yellowish to greenish- 
yellow; sp. gr. 0.915 to 0.925. 

Santal Wood Oil, distilled from wood of Santalum Album. 
The wood (an East Indian product) from which this oil is made is 
frequently called sandal wood, which is a wood, however, that is 
not fragrant and can be used in perfumery for coloring purposes 
only. Santal wood oil has a thick, syrup-like consistency and a 
yellowish color. Copaiba balsam is in some cases substituted 
for santal oil in soap perfumes, as the odor is very similar and 
the cost much less. Sp. gr. 0.975 to 0.985. Optical rotation — 
17° to—19° in a 100 mm. tube. To test for adulteration with cedar- 
wood oil, fatty oils, &c., dissolve 1 volume of the oil in 5 volumes 
of alcohol of 70 per cent by volume; at a temperature of 70° F. 
East Indian santal wood oil should give a perfectly clear solution. 


Coloring and Perfuming. 


335 


West Indian Santal wood oil, however, gives an opaque solution 
in this test, and so will the former after it has been kept for a 
time exposed to air and light. 

Sassafras Oil, distilled from the bark of the root of Sassa¬ 
fras Officinalis ; yellow to red; much used in ordinary soaps, but 
now quite extensively substituted for the purpose by “Safrol’’ 
and by “artificial oil of sassafras,” made from Japan camphor oil. 
The oil of sassafras has a sp. gr. of 1.070 to 1.0S0, and consists 
chiefly of safrol and a very little eugenol. 

Spearmint Oil, distilled from herb of Mentha Viridis ; less 
fine than oil of Peppermint, but has a somewhat characteristic 
odor, different from peppermint; refreshing in tooth soaps and 
dentifrices; colorless to greenish yellow. Sp. gr. 0.925 to 0.960. 

Spike or Spike Lavender, See Lavender. 

Star Anise Oil, from the fruit of Illicium Anisatum ; re¬ 
sembles the oil of anise which is sometimes adulterated with it. 
Colorless to yellowish; sp. gr. 0.980 to 0.990 at 62° F; congeals 
at 55 to 64° F.; consists chiefly of anethol which is also the prin¬ 
cipal constituent of oil of anise. 

Storax, from Liquidamber Orientalise a balsam, used to fix 
other odors; from it is distilled the oil of Storax (sp. gr. 0.890 
—0.900) which may take the place of the balsam in the prepara¬ 
tion of perfumes. 

Tar Oil. Distilled from pine tar; almost colorless when 
just made, it soon turns reddish-brown; tarry odor; sp. gr. 0.970; 
used in soaps in place of tar and said to have the same medicinal 
properties. Beech tar and Birch tar also yield tar oils on dis¬ 
tillation. 

Terpineol, is a liquid principle existing in several essen¬ 
tial oils, and extracted from these and brought into commerce as 
“Lilacine.” It has the odor of the lilac. Being volatile onlyat 
a high temperature, it can be used when the soap is comparative¬ 
ly hot. It is not affected by lye or fatty acids, but its odor 
and color change unless it is kept well stoppered. Thick, color¬ 
less, liquid; sp. gr. 0.940; soluble in alcohol, fatty oils, and vase¬ 
line. Terpineol combines well with such odors as geranium, 
cananga, and santalwood oil. 

Thyme Oil, from leaves and flowering tops of Thymus Vul¬ 
garise (Often misnamed “Oil of Origanum” q. v.) This oil con¬ 
tains as its principal constituent “thymol,” which is valued as a 
preservative and said to in a measure prevent soap from turn- 


336 Coloring and Perfuimng. 

ing rancid; thymol is also used in medicated “thymol soap.” 
Two varieties, the red and the white, areknown. Sp. gr. 0.900 to 
0.935, the oil made from dried herb having 1 a sp. gr. approach¬ 
ing the lower of these figures, while that distilled from fresh 
herbs being more nearly 0.935. The oil should give a perfectly 
clear solution with one-half its own volume of alcohol. The Oil 
of Wild Thyme is distilled from the herb of Thymus Serpyllum 
and has an odor of both thyme and melissa; sp. gr. 0.915 to 0.920; 
contains thymol and carvacrol. Thymene, a by-product of Thy¬ 
mol making, may be used in many cases as a cheap substitute 
for Thyme oil in soaps. 

Thyme oil is mostoften adulterated with turpentine. 

Tolu Balsam, from Toluifera Balsam.um; used to fix other 
odors; the oil distilled from it (sp. gr. 0.935 to 0.975) has a fine 
hyacinth-like odor and is also used in perfumes. 

Vanillin: The odorous constituent of the vanilla bean, is 
made artificially from the sap of the pines. One ounce of it is 
calculated to be equal to 40 ounces of the best beans. Soluble 
in alcohol, water, and glycerin. Sometimes adulterated with 
acetanilide; the melting point of pure vanillin is 79—82°C. while 
adulteration with 25 per cent acetanilide lowers it to 62 ; further¬ 
more pure vanillin is readily and completely soluble in dilute 
caustic soda lye while the adulterated article is only partly so. 

Verbena Oil, from Verbena Triphilla Aloysio, Citriodora. has 
a pleasant, lemon-like odor. It is often adulterated or entirely 
substituted by oil of lemon grass. 

Vetiver Oil, from the roots of Andropogon Muricatus; has 
the property of making the odor of otheroils more lasting. Red¬ 
dish brown, thickly fluid, of intense, orris-like odor. Sp. gr. 
1.015 to 1.025; should be entirely soluble in twice its volume of 
alcohol of 80 per cent by volume. The oil distilled in the island 
of Reunion does not give this latter test, has a specific gravity 
considerably below 1.000, and has a less intense odor. 

WintergrEEN Oil, from leaves of Giultherii Procumbens 
(checkerberry) ; much used for soap. Frequently, not to say 
usually, substituted by birch oil (from Betida Lenta, q. v.) which 
is very similar. The oil of Wintergreen is much used for similar 
purposes as the oil of Peppermint. Colorless to yellowish-red; 
sp. gr. 1.175 to 1.185; optical rotation about —1 in a 100 mm. 
tube; consists chiefly of methyl salicylate (which is also the 
“artificial oil of wintergreen”); frequently adulterated with oil 


Coloring and Perfuming. 


337 


sassafras, petroleum, &c. See also “Artificial Oil of Winter- 
green. 

Ylang-Ylang Oil, from JJnona Odoratissima. One of the 
finest aromatic substances. (Cananga Oil is a cheaper variety 
of the same oil. distilled from the flowers of Cananga Odorata, 
and more frequently used for soaps). Ylang-Ylang oil has a sp. 
gr. of 0.940 to 0.955; optical rotation—45° to—60° in a 100 mm. 
tube. Oil of Cananga has a sp. gr. of 0.910 to 0.920. 

SELECTION AND PREPARATION OF THE PERFUMES. 

The proper selection of the kind and proportions of aromatic 
materials to be used for perfuming’ soaps is a special art, and in 
this respect most soap manufacturers are forced to rely on tried 
formulas, the preparation of a harmonious compound, from the 
numerous ingredients, requiring experience and skill. We there¬ 
fore append a number of such formulas,but will add some special 
remarks for the guidance in selecting a suitable one. 

In the first place, in selecting a formula, it should be exam- 
ined, of course, as to its cost, to see if the price of the soap will fume 
bear it. Then the composition must be considered, whether it con¬ 
tains oils that can affect the color of the soap, as in the case of oil 
of cassia and of cloves for white soap. Then the use of the soap 
is to be considered; a toilet soap must, of course, never be per¬ 
fumed to remind the consumer of the smell of laundry soap; 
tooth soaps are preferably perfumed with oils that have a cool¬ 
ing after-effect on the mouth, notably peppermint, spearmint, 
sage, and sometimes wintergreen; shaving soaps must have very 
little perfume, etc. 

For perfuming milled soaps the special chapter treating of 
these gives some specific instructions. 

For cold-made soap many otherwise good formulas for per¬ 
fumes are not adapted, as some oils undergo a change when they 
are in contact with the raw materials while saponification is be¬ 
ing effected, a number of them being affected deleteriously by 
the strong lye used in the cold process. 

The formulas below are given in parts by weight,but in prac¬ 
tice it will be found more convenient, as a rule, to measure the 
oils in a graduated glass, instead of weighing them. The weight 
of a majority of the different oils is sufficiently similar to permit 
of measuring in this manner without causing bad results. 

If possible the oils should be mixed a few weeks before they 


338 


Coloring and Perfuming. 


Preparing the a re required to give the perfume time to blend into a harmonious 

perfume. r 

compound before using. 

In toilet soaps it is always advisable to use some of the tinc¬ 
tures, etc., which have been described as serving to make the odor 
more lasting; as the loss of the latter during the time the soap 
is in the store would detract from its value, perhaps make it un- 
salabe, and hurt the trade. These “fixing agents” are especially: 
The tinctures of Musk, Civet, Ambergris, Benzoin, Tolu, Balsam 
of Peru, and Storax; also Orris Root (finely powdered, or the 
tincture). 

Additions of this kind should not be omitted for the further 
reason that they permit of some economy in essential oils, a small¬ 
er quantity of which will have a stronger and more lasting effect 
than where no such addition is made. 

The tinctures may be bought ready for use, or can be made 
by dissolving or extracting the drugs mentioned with alcohol in 
the following manner: 

TINCTURE OF MUSK. 


Musk in grain. 1 oz. 

Civet. 80 grains. 

Carbonate of potash. oz. 


Triturate the ingredients until no more ammoniacal vapors 
are evolved. Then gradually add two quarts of boiling water, 
and lastly add 2 quarts of strong alcohol. Bet stand at least a 
week before using. 

Or, 


Musk, in grain. 1 oz. 

Alcohol. 2 quarts. 

Granulated sugar. 2 ozs. 

Potash. 1 oz. 


Triturate the musk and sugar, gradually adding the alco¬ 
hol. Let stand as long as possible before using, occasionally 
stirring. 

Or , 


Musk, in grain. 1 oz. 

Alcohol . 10 ozs. 


Triturate the musk with the alcohol, using a little ammonia 
water (about ^ oz.) with it, and shake occasionally for five or 
six days. After filtering, extract again with only 5 ozs. of alco- 











Coloring and Perfuming. 


339 


hoi; repeat a third time and use the weak tincture in place of al¬ 
cohol the next time. 

For cheap product, American musk, from the American American musk. 
Muskrat, is sometimes used, by steeping’it for a few days in warm 
water, and then adding an equal volume of alcohol. 

TINCTURE OF CIVET. 


Civet. 2 ozs. 

Orris root (ground). 3 ozs. 

Alcohol . ... 5 quarts. 


Triturate the civet and orris root, gradually adding the 
alcohol. 

Or, 


Civet. 8 ozs. 

Oil Lavender. 4 ozs. 

Alcohol. 5 lbs. 


Rub the civet and the oil together in a warm mortar, add the 
alcohol and shake well. Rest, filter and make a second extrac¬ 
tion as described for tincture of musk. 

TINCTURE OF AMBERGRIS. 

Ambergris. 2 ozs. 

Alcohol. 3 quarts. 

Treat the same as for civet. The ambergris is made into 
small pieces with a knife, or may be triturated with some sugar. 
Let stand, for several weeks at least before using. 

TINCTURE OF BENZOIN. 


Benzoin. 1 lb. 

Alcohol .2 lbs. 

TINCTURE OF BALSAM OF PERU. 

Balsam of Peru. 1 lb. 

Alcohol .. 2 lbs. 


This tincture has a dark brown color, and a pleasant odor. 
It should be used only in soaps whose color is not affected by it. 

TINCTURE OF STORAX. 

Storax is treated in the same manner as Benzoin and Balsam 
of Peru. 














340 Coloring and Perfuming. 

TINCTURE OF ORRIS ROOT. 


Powdered Orris Root. 1 lb. 

Alcohol.. 10 lbs. 


This tincture is of value for fixing other odors, but is some¬ 
times also sold by itself as a cheap violet perfume. Ordinarily 
orris root is used in soaps in the form of an extremely fine 
powder. 


TINCTURE OF TOLU. 

Balsam of Tolu is treated with alcohol like Benzoin and 
Balsam of Peru. 


TINCTURE OF VANILLA. 

Vanilla. 1 lb. 

Alcohol. 10 lbs. 

When exhausted the vanilla is stood aside, exposed to the 
air, for a time, when the odor will be renewed and may be used 
by a second extraction. 

PERFUMES FOR LAUNDRY SOAP. 

The following are some formulas for the perfuming of laun¬ 
dry soaps. The quantities are calculated for a frame of about 
1,200 lbs. and may, of course, be changed to suit. 

1. Oil of Mirbane. 1)4 lbs. 

2. Oil of Sassafras. 

3. Oil of Mirbane.. 

Oil of Citronella 

4. Oil of Citronella 
Oil of Mirbane.. 


5. Oil of Citronella. 1 lb. 

Oil of Cloves. y lb. 

6. Oil of Mirbane. 1)4 lbs. 

Oil of Sassafras. >4 lb. 

7. Artificial Oil of Sassafras.... 1 lb. 

Oil of Citronella. 1 lb. 


(A little oil of Cedarwood may be added, if desired, and will 
make the odor more lasting.) 


1)4 lbs. 

1)4 lbs. 
Va lb. 

12 ozs. 
4 ozs. 

















Coloring and Perfuming. 


341 


8. Oil of Lavender. 

.. 1 

lb. 

Oil of Citronnella. 

.. 1 

lb. 

9. Oil of Lavender. 

.. 1 

lb. 

Oil of Thyme (white). 

.. 3^ 

lb. 

10. Oil of Lavender. 

. . 4 

parts. 

Oil of White Thyme. 

. . 1 

part. 

Oil of Rosemary. 

.. 2 

parts. 

Oil of Citronella. 

.. 1^ 

parts 

11. Oil of Caraway. 

.. 1 

lb. 

Oil of Fennel. 

.. ^ 

lb. 

Oil of Cloves. 

.. % 

lb. 

12. Oil of French Pennyroyal*.. 

.. 2 

lbs. . 

Oil of Thyme (white). 

. . 10 

oz. 

Oil of Lavender flowers. 

.. 10 

oz. 

Oil of Caraway chaff. 

.. 5 

oz. (For white soap) 

13. Oil of French Pennyroyal*. 

.. 1 

lb. 

Oil of Cassia. 

.. 1 

lb. 

Oil of Cloves. 

.. % 

lb. 

Oil of Lavender (spike). 

.. 1 

lb (For colored soap) 

* This oil (0/. Mentha Pidegii ) 

must 

not be mistaken for 


the American Oil of Pennyroyal which is quite different. 

PERFUMES FOR COLD-HADE SOAPS. 

As already stated many odors are spoiled by being- introduced 
into a cold-made soap, but the number of perfume formulas that 
could be g-iven for these soaps is almost unlimited. The follow¬ 
ing selection will probably be amply sufficient, however, for all 
ordinary requirements. The proportion of the compounded per¬ 
fume to be used in the soap must be left to the discretion of the 
manufacturer. For laundry soaps by the cold process the fore¬ 
going “Perfumes for Laundry Soap” may also be used; the fol¬ 
lowing formulas are more especially for toilet soaps. 


Oil of Bitter Almond .... 

.... 4 

parts. 

Oil of Bergamot. 

... 1 

part. 

Oil of Bitter Almond.. .. 

... 3 

parts. 

Oil of Bergamot. 

.... 1 

part. 

Oil of Citronella. 

.... 1 

part. (Almond.) 
























342 


Coloring and Perfuming. 


Artificial Oil of Bitter Al- 


mond. 

.22 

parts. 

Oil of Lavender. . . . 

. 8 

parts. (Almond.) 

Oil of Lavender. . .. 

. 2 

parts. 

Oil of Bergamot. . . 

. 2 

parts. 

Oil of Cassia. 

. 1 

part. 

Tincture of Bciizoe. 

. 2 

parts. 

Tincture of Balsam 

of Peru. 1 

part. (Violet..) 

Oil of Lavender .. . 

.12 

parts. 

Oil of Cassia. 

.15 

parts. 

Oil of Portugal . . . . 

. 4 

parts. 

Oil of Caraway. . . . 

.7 

parts. 

Oil of Geranium . . 

.2 

parts. (Windsor .) 

Oil of Lavender.. .. 

. 1 

part. 

Oil of Citronella .. . 

. 1 

part. - 

Oil of Palmarosa. . 

., 1 

part. (Rose.) 

Orris Root, powdered.20 

parts. 

Oil of Bergamot.. . . 

.15 

parts. 

Oil of Geranium . . . 

. 7)4 parts 

Oil of Linaloe. 

. 9 

parts. 

Tincture of Musk.. 

. 1 

part. (Lily of the Valley) 

Oil of Citronella.. ., 

.23 

parts 

Oil of Sassafras. . . . 

. 8 

parts. 

Oil of Caraway.... 

. 7 

parts. (Honey.) 

» this may be added, 

if desired, Oil of Thyme, 12 parts.) 

Oil of Cassia. 

.20 

parts. 

Oil of Rosemary . . . 

.10 

parts. 

Oil of Mirbane.... 

. 2 

parts. (Violet.) 

(Use in Palm Oil Soap.) 

Oil of Geranium .. . 

.20 

parts. 

Oil of Mirbane.... 

. 3 

parts. 

Oil of Bergamot. . . 

.10 

parts. 

Oil of Cassia. 

. 1 

part. (Violet.) 

Oil of Linaloe. 

.15 

parts. 

Oil of Cananga .. . . 

. 5 

parts. 

Oil of Palmarosa . . 

. 2)4 parts. (Lily of the Valley) 



































Coloring and Perfuming. 343 


Oil of Bergamot . 

... 4 

parts. 

Oil of Lemon . 

. . . 6 

parts. 

Oil of Portugal . 

. . . 4 

parts. 

Oil of Lavender . 

... 3 

parts. 

Oil of Rosemary. 

.... 1 

parts. (Lau de Cologne.) 

Oil of Lavender. 

. . . 1 

part. 

Oil of Caraway. 

. . . 1 

part. 

Oil of Cassia. 

... 1 

part. 

Oil of Thyme . 

... 1 

part. (Omnibus.) 

Oil of Citronella . 

.... 3 

parts. 

Oil of Bergamot . 

.... 2 

parts. 

Oil of Melissa . 

. ... 1 

part. (Hotie} T .) 

Oil of Bergamot . 

. ...18 

parts. 

Oil of Sassafras . 

. .. 5 

parts. 

Oil of Cloves . 


parts. 

Oil of Thyme .. 

. .. 5 

parts. 

Oil of Neroli . 

— 2^ parts. (Bouquet.) 

Oil of Rose . 

. .. 2 

parts. 

Oil of Geranium . 

.. . 3 

parts. 

Oil of Cinnamon . 

. ... 1 

part. 

Oil of Bergamot. 

.... 2 

parts. 

Oil of Cloves. 


little. (Rose.) 

Oil of Caraway. 

. . ..12 

parts. 

Oil of Bergamot. 

....20 

parts. 

Oil of Lavender. 

. . . 8 

parts. 

Oil of Thyme, white . . .. 

. ... 7 

parts. 

Oil of Cloves . 

. . .. 1 

part. (Shaving.). 

Heliotropin . 

....20 

parts, j 

parts, i Dissolve in Oil 

Coumarin . 


Oil of Petitgrain . 

....25 

parts. 

Oil of Gerapium . 


parts. 

Oil of Bitter Almond .. .. 

....10 

parts. (Heliotrope.) 

Oil of Geranium . 

. ...10 

parts. 

Oil of Bergamot . 

. ...10 

parts. 

Tincture of Orris Root . . . 

. .. . 6 

parts. 

Tincture of Benzoin. 

... 6 

parts. (Violet.) 






































344 


Coloring and Perfuming. 


Oil of Bergamot. 

. 8 

parts. 

Oil of Rose .. 

. 1 

part. 

Oil of Cloves. 

. 1 

part. 

Tincture of Musk. 

.... 1^ 

parts. 

Oil of Anise. 

. 3 

parts. 

Oil of Citronella. 

. 3 

parts. 

Oil of Lavender. 

. 2 

parts. 

Oil of Bergamot. 

. 5 

parts. 

Oil of Cloves. 

. 1 

part. 

Oil of Thyme. 

. 3 

parts. 

Oil of Peppermint. 

. 2 

parts. 

Oil of Caraway . 

. 4 

parts. 

Oil of Lavender. 

. 1 j4 

parts. 


(To this may be added, if desired, Oil of Bergamot, 2 parts.) 


Oil of Verbena. 

.12 

parts. 

Oil of Bergamot. 

.12 

parts. 

Oil of Citronella. 

.10 

parts. 

Oil of Palmarosa. 

.12 

parts. 

Tincture of Musk. 

. 1 

part. (Honey.) 

Oil of Thyme. 

. 3 

parts. 

Oil of Fennel. 

9 

parts. 

Oil of Caraway. 

. 2'A 

parts. 

Oil of Lavender. 

. 2 

parts. (Cocoanut 

Oil of Lavender. 

. 6 

parts. 

Oil of Caraway. 

. 4 

parts. 

Oil of Star Anise .... 

. 3 

parts. 

Oil of Fennel. 

. 3 

parts. (Cocoanut 


An old-fashioned but very good formula is the following: 

Powdered Orris Root.5,000 parts. ) Mixed with the 

Powdered Orange Peel.2,000 parts. ) melted fat. 

Liquid Storax.1,000 parts.—Dissolved in a lit¬ 

tle hot fat and strained into the bulk of the latter. 


Oil Lavender (French) . .. 200 parts. 

Oil Bergamot. 300 parts. 

Oil Geranium. 100 parts. 

Balsam Peru. 50 parts. 


Added to the soap 
toward the end 
of crutching,to¬ 
gether with the 
musk. 




































Coloring and Perfuming. 


345 


Musk. 10 parts. — Rubbed together 

with some of the lye or a little glycerin. (Violet.) 

PERFUflES FOR (BOILED) MILLED TOILET SOAPS. 

The following formulas are from the great number used for 
incorporation into ready formed soap, whether by milling or re- 
melting. Some of them no doubt would also give satisfaction 
for cold-made soap. 


The following is a very fine fancy odor: 

Oil of Thyme (white). 

. 6 parts. 

Oil of Orange. 

.. 6 parts. 

Oil of Bergamot. 

. 18 parts. 

Oil of Caraway. 

. . 9 parts. 

Oil of Lavender. 

..16 parts. 

Oil of Clove. 

. . 9 parts. 

Oil of Cassia. 

.. 6 parts. 

Balsam of Peru. 

.. 6 parts. 

Oil of Cinnamon. 

. .20 parts. 

Oil of Geranium. 

. . 15 parts. 

Oil of Valeria. 

% part. 

Tincture of Benzoin. 

..14 parts. 

Tincture of Musk . 

. . 17 parts. (Musk.) 

Oil of Cassia. 

.. 3 parts. 

Oil of Lavender. 

.. 2 parts. 

Oil of Caraway. 

.. 3 parts. (Windsor.) 

Oil of Orange. 

.250 parts. 

Oil of Neroli. 

.200 parts. 

Oil of Rose. 

. 20 parts. (Orange Flower.) 

(To this may be added, if desired, Musk 1 part.) 

Oil of Lavender, Montbl. 

. . . . 5 lbs. 

Oil of Geranium, rect. on roses 1 lb. 

Oil of Geranium, African 

. . . . 3 lbs. 

Oil of Geranium, Turkish 

. . . . 1 lb. 

Oil of Patchouli, Penang. 

. ... y A ib. 

Oil of Verbena, French. . 

.... # ib. 

Oil of Vetivert, Spanish. 


Oil of Cloves, Bourbon. . . 

. . . 1 lb. 

Oil of Bergamot. 

.... 2 lbs. 

Tincture of Musk. 

. ... 1 lb. 

Tincture of Ambrette. . .. 

. ... 1 lb. (White Rose.) 






























346 


Coloring and Perfuming. 


Oil of Cinnamon. 

. . ..60 

parts. 

Oil of Cloves. 

. . .60 

parts. 

Oil of Caraway. 

. . ..50 

parts. 

Oil of Anise. 

. . ..30 

parts. 

Oil of Cedarwood ... 

....20 

parts. 

Oil of Sassafras. 

. .15 

parts. 

Oil of Lavender. 

. . ..15 

parts. (Windsor.) 

Oil of Rose. 

. . . . 8 

parts. 

Oil of Rose Geranium . 

. . . . 6 

parts. 

Oil of Cinnamon . 

. . . . 2 

parts. 

Oil of Berg-amot. 

. . . . 4 

parts. 

Tincture of Civet. 

. . . . 2 

parts. (Rose.) 

Oil of Berg-amot. 

. . . .12 

parts. 

Oil of Lavender. 

. . .. 8 

parts. 

Oil of Caraway. 

. . . . 6 

parts. 

Oil of Peppermint. 

. . .. 3 

parts. 

Oil of Thyme. 

.... 2 

parts. (Elder Flower.) 

Oil of Lavender. 

. . 2 

parts. 

Oil of Linaloe. 

. ... Y\ parts. ( Lily of the Valley) 

Oil of Lavender. 

. . .. 6 

parts. 

Oil of Peppermint. 

. ... 2 

parts. 

Oil of Carawav . 

. . . . 2 

parts. 

Oil of Lemon. 

.1 

part. 

Oil of Thvme. 

j 


part. 

Oil of Rosemary. 

. . .. % 

part. (Marsh Mallow.) 

Oil of Lemongrass. 

...50 

parts. 

Oil of Citronella. 

...200 

parts. 

Oil of Cloves. 

. .. 30 

parts. 

Oil of Cassia. 

..30 

parts. (Honey.) 

Oil of Berg-amot. 

. ..10 

parts. 

Oil of Geranium . 

. . . . 2 

parts. 

Oil of Neroli. 

. . .. 1 

part. 

Oil of Lavender. 

... 1 

part. 

Tincture of Civet. 

. . . . 1 

part. 

Tincture of Musk. 

. . . . 1 

part. 

Orris Root (powdered) . 

....40 

parts. (Violet.) 





































Coloring and Perfuming. 


347 


Heliotropin . 

.10 

parts. 


Vanillin. 

.. 2 

parts. 


Musk. 


part. 


Balsam Peru. 


parts. 


Oil Geranium, Afr. 

.30 

parts. 

(Heliotrope.) 

Oil of Thyme . 

. 2 

parts. 


Oil of Caraway. 

. 2 

parts. 


Oil of Cassia. 

. 1 

part. 


Oil of Lavender. 

. 1 

part. ( 

Elder Flower.) 

Oil of Bitter Almond. 

.50 

parts. 


Oil of Bergamot. 

.20 

parts. 


Oil of Cloves. 

.10 

parts. 


Oil of Geranium. 

. 5 

parts. 


Oil of Cedarwood. 

. 5 

parts. 


Oil of Sassafras. 

. 5 

parts. 


Tincture of Musk .. 

.50 

parts. 


Tincture of Tonka beans.. 

.10 

parts. 


Tincture of Civet . 


parts. 

(Almond.) 

Oil Linaloe. 

1 

lb. 


Balsam Peru.. 

10 

ozs. 


Bitter Almond. 

2 

ozs. 


Tincture Benzoe. 

15 

ozs. 


Bergamot. 

4 

ozs. 

(Heliotrope.) 

Oil of Bergamot. 

4 

parts. 


Oil of Neroli. 

2 

parts. 


Oil of Santalwood . 

2 

parts. 


Tincture of Vanilla . 

8 

parts. 


Tincture of Civet. 

8 

parts. 

(Frangipanni 

Oil of Bergamot. 

8 

parts. 


Oil of Lavender. 

4 

parts. 


Oil of Cloves. 

2 

parts. 


Oil of Nutmeg. 

1 

part. 


Tincture of Musk. 

4 

parts. 

(Millefleur). 

Oil of Linaloe. 

5 

parts. 


Oil of Bitter Almond. 


part. 


Oil of Cloves. 

4 

parts. 


Lilacine. 

24 

parts. 

(Shaving.) 





































348 


Coloring and Perfuming. 


Oil of Citronella. . 
Oil of Lavender.. . 

Oil of Caraway. . . 
Oil of Lavender.. 
Oil of Rosemary. . 
Oil of Star Anise 


3 parts. 

1 part. (Honey.) 

3 parts. 

2 parts. 

2 parts. 

)4 part. (Honeysuckle.) 


Oil of Opoponax. 50 parts. 

Oil of Citronella .250 parts. 

Oil of Cinnamon (Ceylon).. 15 parts. 

Oil of Palmarosa.100 parts. 

Vanillin. 5 parts. 

Coumarin. 2 parts. 

Musk. 1 part.* (Opoponax.) 

*Rubbed together with sugar, or an equivalent in tincture. 


Oil of Wintergreen. 1 part. 

Oil of Sassafras. 1 part. 

Oil of Rose. 6 parts. 

Oil of Geranium . 25 parts. 

Oil of Bergamont.100 parts. 

Oil of Lavender. 20 parts. 

Oil of Cinnamon. 15 parts. 

Tincture of Tonka beans. . 50 parts. 
Tincture of Coumarin. 50 parts. 

Tincture of Musk. 25 parts. 

Heliotropin. 5 parts. 

Oil of Lavender,mont-blanc 4 parts. 

Oil of Caraway Seeds . 2 parts. 

Oil of Thyme, red. 1 part. 

Oil of Rhue. >4 part. 

Oil of Thyme, white. 2/4 parts. 

Oil of Lavender,mont-blanc 5 parts. 

Oil of Caraway Seed. 2)4 parts. 

Oil of Marjoram. 2 parts. 


(Tooth Soap.) 


(New Mown Hay.) 


(Brown Windsor.) 


(Guimauve.) 






























Coloring and Perfuming. 


349 


Oil of Palmarosa. 

Oil of Lavender Flowers, 

2 

parts. 

strong-. 

2 

parts. 

Oil of Lavender Spike, flo- 



wers. 

1 

part. 

Oil of Rhue. 


part. 

Oil of Anise. 

% 

part. 

Oil of Palommier. 

1 

part. 

Oil of Berg-amot. 

7 

parts. 

Oil of Palmarosa. 

6 

parts. 

Oil of Geranium. 

5 

parts. 

Oil of Cedarwood. 

2 

parts. 

Oil of Berg-amot. 

120 

parts. 

Oil of Orang-e peel. 

100 

parts. 

Oil of Lavender. 

60 

parts. 

Oil of Palmarosa. 

30 

parts. 

Oil of Ging-ergrass. 

15 

parts. 

Oil of Cassia.. 

25 

parts. 

Oil of Citronella . 

25 

parts* 

Oil of Cloves. 

15 

parts. 

Oil of Santalwood. 

25 

parts. 

Oil of Bitter Almond. 

5 

parts. 

Orris root, finely powdered. 100 
Musk, rubbed up with milk 

parts. 

sug-ar. 

1 

part. 

Oil of Lavender. 

15 

parts. 

Oil of Neroli.. 

30 

parts. 

Oil of Berg-amot. 

120 

parts. 

Oil of Geranium (Fr.).... 

25 

parts. 

Tincture of musk. 

15 

parts. 

Tincture of Civet. 

10 

parts. 


(A spicy odor for 
dark soap.) 










































































































































CHAPTER XVII 


Pressing the Soap. 


When the soap, after solidifying- in the frame, has been cut 
into slabs, bars, and cakes, it requires a period of drying before 
it is ready to be pressed, the time required for drying varying 
according to the nature of the soap, and the system of drying 
employed. (The effect of different methods of drying have been 
previously explained.) Frequently, in the pressure of business, 
soap is also pressed without drying properly. 

Milled soap is ready for the press almost immediately after 
coming from the plodder. Other toilet soaps, cold-made as well 
as boiled, should dry at least until each cake is covered with a 
hardened layer of “skin” on the surface. If this skin is allowed 
to become too thick, through too long drying, it will cause the 
cake to crack in pressing; but such soap can be made into ex¬ 
ceedingly handsome cakes by a simple remedy, namely by cutting 
off the outer-most solid part of the skin. This process is some¬ 
times adopted purposely with the object of giving the soap an 
improved appearance, as well-dried cakes of this kind, from which 
the hardest part of the skin has been removed by drawing each 
surface over the knife of an ordinary wood plane, will dry out less 
afterwards, will have a smoother surface, and will show the de¬ 
sign of the dies in much sharper outline, than a soap that was 
simply pressed after drying somewhat. It may here be remark¬ 
ed that the smooth finish of a soap is improved also by using as 
thin wire for cutting as possible. 

Where for any reason the process just described is not suitable 
—as when it is too expensive, or when the cakes were not cut in 
size to make allowance for the shaving taken off—the cakes may 




352 


Pressing the Soap. 


Pressing twice. 


be softened by means of warming- them, before pressing-. The 
latter method is also frequently adopted when the shape of the 
finished cake is such that the soap cannot easily be cut to corres¬ 
pond to its outlines, as for example when oval or round cakes are 
to be pressed from pieces cut square. 

A special method of preparing- the soap for pressing- consists 
in exposing- it for a very few moments to the direct action of a 
current of very hot steam turned upon the cakes. The steam 
causes a chang-e in the character of the soap on the surface and 
closes up all its pores; the soap thereby acquires a beautiful fin¬ 
ish which remains after pressing-,and will be better able to stand 
exposure to unfavorable weather. 

The weather prevailing- when soap is pressed is also of 
some moment, for most soaps sweat on days when the atmosphere 
is saturated with moisture and are then in poor condition for 
pressing. On such days the windows of the press-room must be 
closed to keep out the moisture. A clear, brig-ht day is most 
favorable for this operation. 

The cakes are previously cut to conform as nearly as possible 
to the size and shape of the die, in order not to strain the cohe¬ 
sion of the particles too much in pressing-, and as said before, 
this may have to be supported by the warming- of the cakes. 
Boiled-down soaps and some others, are so short in texture that 
they cannot be pressed at ail, or at least only into very flat bars, 
for which reason they are in most cases merely stamped with the 
necessary letters without pressing the cake itself. 

To prevent cracking, and to bring out the design of the dies 
well, it is sometimes necessary to press the soap twice, once in a 
plain die, which merely shapes the cake, and then in another die 
bearing the required design. In less extreme cases it is merely 
necessary to close the dies twice on each cake. 

The dies themselves must be made in accordance with the 
grade of the soap to be pressed in them, as has been explained in 
Chapter V; and the design must be so cut that the soap may 
withdraw easily from the die, without sticking. Fine lines and 
sharp corners must be made as strong as possible, and must be 
adapted to the texture of the soap to be pressed. 

Brass dies cause brown spots to appear on soap, especially if 
the latter contains free alkali,which attacks the metal of the dies. 
Laundry soaps, especially, are therefore better pressed in iron 
dies. The smoother the dies, the handsomer will be the soaps 


Pressing the Soap. 


353 


pressed in them, and some manufacturers use even nickel-plated 
dies for this reason. 

A properly dried soap will hardly stick to the dies in press- Lubricating the 
ing\ if the latter are properly constructed. But frequently soap 
is pressed in a more or less “green” state, when it becomes nec¬ 
essary to use some lubricant or other to prevent sticking. Water 
or glycerin alone are not well adapted for the purpose,but a mix¬ 
ture of the two gives good results, as does also vaseline. Alcohol 
or salt water are used similarly, but the latter is not to be recom¬ 
mended, as it will crystallize on the surface of the soap. Vinegar 
also is used, but does not act equally well in all soaps. These 
liquids are applied by simply drawing a sponge, moistened with 
one or the other of them,across the die after pressing a few cakes, 
or whenever the soap shows an inclination to stick. 

At the ends of cakes of soap, especially in milled soap, there 
is usually seen a mark made by the effect on the grain of the 
pressing operation. As this is evidently the result of the change 
of shape which the cake undergoes in the die, a process has been 
patented of feeding the bar of soap coming from the plodder di¬ 
rectly to the die, without previously cutting the bar into cakes, 
so that the die cuts off the required amount of soap. We are not 
aware of this having been adopted in practice (U. S. Patent No. 

461,973). 

It remains to say a few words about the care of the dies, 
which in most factories represent quite a little capital: 

The life of a die depends entirely on the press, and on the 
care exercised in setting or fastening it to the press, and fre- care of the dies, 
quent examinations should be made to ascertain the condition of 
both press and die. 

As to the press, it is necessary that the slide or part to which 
the upper die is fastened should move easily, yet steadily, with¬ 
out shake in its bearings or guides, and this point should be ex¬ 
amined daily, as pressers have been known to loosen the bolts 
in order to have easier work, and by this means ruin the die 
with a few impressions. 

It is therefore very essential that a press should be so con¬ 
structed that the guides can be accuratel} 7 adjusted, both at top 
and at bottom, and securely fastened when this adjustment has 
been accomplished. 

To fasten a die in the press, we should suggest to first place 
the upper die in its place in the slide and merely fasten the cap 


354 


Pressing the Soap. 


or set-screw, whichever may be used, with the fingers, to hold it 
in place; then place the box containing the lower die on the bed¬ 
plate and carefully lower the slide, so that the upper die will en¬ 
ter the box without damaging the edges. 

Holding the slide in this position by keeping the foot on the 
lever, loosen the cap or set-screw and place the box accurately, 
so as to place the clamps which fasten the box in the most con¬ 
venient place, but so that the bolts will not touch the flanges or 
box to twist or strain the latter when fastened, and fasten the 
nuts or bolts with the fingers. 

Now fasten the upper die securely. Before the nuts or bolts 
holding the box in place are fastened, endeavor to pull or push 
them in either direction to ascertain their exact position. Should 
they shift, put them as near as possible in the middle of such 
motion and again turn down the nut or bolt and continue this un¬ 
til the play is overcome. Then fasten with a wrench, and care¬ 
fully move the upper die up and down to see that it enters the 
box without striking it in the least. 

You can then press a few bars of soap and again ascertain 
the accuracy of your work, and also see that the bolts or nuts 
holding the box are securely fastened. 

The guide pins now very much used relieve the evil of care¬ 
less setting very much, } T et great savings in the cost of repairs 
can be secured by following the foregoing instructions. 


PART IV. 







































































































































' 

. 


































CHAPTER XVIII. 


Special Soaps. 


FLOATING SOAP. 

Floating' soap, as made in this country since a comparatively 
recent time, is a soap into which air has been forced in the pro¬ 
cess of crutching, whereby its bulk is enlarg-ed so as to cause it, 
when hardened, to float on the water. The object of this gen¬ 
erally is perhaps not so much this property of floating- as the fact 
that such a soap, when in use, presents a larger surface to the 
action of the water, and consequently dissolves and washes more 
rapidly. It is also obvious that any soap in a melted state can 
be made to float by the simple process of incorporating- air as 
stated; but ordinarily only a white soap is so treated. 

Floating- soap may be made by the cold method, but half¬ 
boiling-, as described on page 2b4, is preferable to it, if indeed 
the boiling- process is not employed. In fact, a half-boiled soap 
is sometimes very apt to turn out floating- against the desire of Floating soap by 
the soap maker. Still another method consists in remelting and ' e "" ltl,,w ' 
crutching a (white) soap that has been previously dried some¬ 
what by exposure to the air; this proceeding may be advantage¬ 
ous for working up scraps, or when the manufacture is not 
carried out on a sufficiently large scale to warrant making a 
separate boil. 

It is self-evident that floating soaps, being of themselves stock for floating 
more than usually soluble, should be made largely from stock 
which naturally yields a less soluble soap, such as tallow, and 
that they should contain less water—rather than more—than 
ordinary soap. This latter point apparently is not as generally 




358 


Special Soaps. 


understood as it should be, to judge from the numerous formulas 
extant calling for the addition of water to the soap. 

For the stock, only selected, fresh, white fats and oils are 
used. Probably no two manufacturers use exactly the same 
combination, and an equally good soap may be made from vari¬ 
able proportions of tallow, lard, or lard oil, cotton stearine, and 
cocoanut oil. Cotton seed oil should be used sparingly, if at all. 
A good soap results from tallow and 10 to 20 per cent of cocoa- 
nut oil, with or without the addition of some lard. The addi¬ 
tion of cocoanut oil in this proportion is desirable from a num¬ 
ber of points of view, especially, however, because its low solid¬ 
ifying point permits of air being crutched into it at a compara¬ 
tively low temperature and because it adds lathering qualities to 
the soap composed so largely of tallow. Tallow, on the other 
hand, gives it lasting quality. Rosin is rarely used in a floating 
soap, and then only of the lightest color. 

Boiling the soap. The stock must be thoroughly saponified with pure lye and 

finished in the same manner as described for “White Settled 
Soap,” Chapter VII., page 205. The soap is allowed to settle 
and left in the kettle to cool to a temperature between, say, 170 
and 180 F., at which it assumes the consistency most favorable 

„ ... for crutching. It may here be remarked that the exact temper- 

Crutchmg. ° J * 

ature most suitable for the purpose depends somewhat on the 
composition of the stock, and may be ascertained more definitely 
than stated above in accordance; a pure tallow soap, for instance, 
would be apt to be too thick for crutching even before it could 
be made to froth sufficiently. If allowed to cool too far, part of 
the soap will stick to the sides of some crutchers, and must then 
be scraped out into the frames and there crutched again to pre¬ 
vent excessive warping through unevenness of the contents of 
the frames. If a crutcher is used that automatically scrapes the 
soap from the sides while working, and cuts up the lumps of 
soap forming, the necessity of recrutching in the frame on 
account of this difficulty will of course be avoided. On the other 
hand, if the soap is crutched while too hot, it will go down 
again in the frame before cooling, and the lower part will be too 
heavy to float. 

When the soap has cooled and thickened sufficiently in the 
kettle, as stated, crutching is commenced. The exact proceed¬ 
ing now depends on the style of crutcher used; the machines 
having a vertical screw are filled with pure soap (no filling be- 


Special Soaps. 


359 


ing used for White Floating* soap), so that the cylinder which 
surrounds the screw still projects above the soap, as the latter 
must have room to expand. Besides, the air is incorporated 
more rapidly when the machine is filled in this manner, as the 
soap falling* over the rim of the center-tube catches the air more 
readily than if the machine had been filled above the tube. 

When the Strunz crutcher is employed, a rapid method of oper¬ 
ating- consists in first filling the machine to only one-half of its 
capacity, crutching- for about three minutes, and then filling- the 
machine to within a few inches of the top, when only enough 
crutching will be required to mix both portions well. In this 
manner a frame of soap is ready in from 5 to 8 minutes, no mat¬ 
ter how heavy it naturally is. As the frothy soap in this case 
does not permit of judging exactly how much soap the crutcher 
contains, it is weighed into the machine. 

The exact length of time required for crutching depends on 
the temperature, the consistency and the proportion of water in 
the soap, and on the style of machine used for the purpose; the 
operation is continued until the soap is slightly foamy. It is 
then run into iron frames, where it cools rapidly, and as it falls 
somewhat in the center on cooling—the more so the lighter it is 
x —the edges may be pressed down when the soap begins to harden. 

For perfuming Oil of Lavender is generally used, but, of 
course, any other white oil may be employed. 

The best disposition of the nigre in such a case is a matter 
depending altogether on careful judgment; it will not usually be 
safe to use it over on a second batch. 

If fatty acids (of cottonseed, &c.) are used in the stock, it 
is quite feasible to use carbonate of soda for saponification of 
this particular stock. 

TRANSPARENT SOAP. 

General Remarks. 

Transparent soap consists of ordinary soap, to which certain 
additions have been made for the purpose of rendering it trans¬ 
parent. Ordinary soap is opaque because of its Crystalline 
texture, and the process of rendering it transparent by certain 
admixtures has been aptly compared with the transparency as- 

. . , , . •, Original process 

sumed by snow when it is soaked in water. Originally it was 
made, by dissolving in about one-half its own weight of alcohol, 
a dry, neutral, boiled soap, and afterwards distilling off again— 


360 


Special Soaps. 


Modern 


Stock. 


by means of the water bath—the greater part of the alcohol so 
employed, leaving- the soap behind in an amorphous condition. 
The soap obtained by this method is unequaled by the transpar¬ 
ent soap made by any other process, as the soap—to begin with— 
was most thoroughly saponified, and the fact that it is dissolved 
in alcohol, permits of settling out at this stage a considerabe 
amount of impurities which are present in soaps even that have 
been made of the very finest ingredients; the final product is con¬ 
sequently more nearly neutral, purer and clearer than a soap to 
which alcohol has simply been added in small proportions. How¬ 
ever, this process is now but rarely used, as it is too expensive in 
comparison with later methods which have been more generally 
adopted. 

processes At present, the transparency of a soap is often produced by 
means of the simple addition of alcohol. In most cases part of 
the alcohol required for the purpose is substituted by glycer¬ 
in and sugar or sugar dissolved in water. The sugar so¬ 
lution causes even greater transparency than does alcohol, and 
in order to counteract its tendency to soften the soap, sal soda is 
added in those cases where the alcohol is substituted entirely by 
glycerin and sugar solution. Transparent soaps made in the 
latter way— i. c., without alcohol altogether, and hardened b} T 
sal soda—are very liable to effloresce on keeping. The lowest 
grade, probably, is that in which boiled starch is used to per¬ 
form the office of glycerin. 

Glycerin, although not exactly absolutely necessary, makes 
the soap clearer and does not evaporate like water and alcohol; 
for this reason its use is to be recommended, inasmuch as it re¬ 
duces the required amount of alcohol and sugar water. It is also 
less expensive than alcohol; but used in too large proportions it 
causes sweating of the soap. 

The proportions used of alcohol, glycerin, and sugar solu¬ 
tion, it will be noticed, are not definitely fixed, but var}- in dif¬ 
ferent formulas, as will be seen from the examples given here¬ 
after. By using more or less castor oil in the stock, the required 
amount of alcohoi is reduced, as this oil forms a naturally more 
transparent soap; too much of it however, makes the product soft 
and sticky and also reduces its lathering properties. 

The stock for transparent soaps may be the same as for the 
non-transparent toilet soaps, and is generally tallow, with from 
25 to 100 per cent cocoanut oil, and more or less castor oil. Stear- 


1 


Special Soaps. 


361 


ine is also used quite frequently. Whatever the stock, it must 
be very carefully purified by lye and alum, in the manner already 
described, as any impurities remaining- are particularly notice¬ 
able in transparent soap. Old rancid fats will not make clear 
transparent soap; the latter would become “flakey.” It is also 
uselul to remember in this connection that the more cocoanut 
oil the soap contains, the longer it may be left to cool before 
framing-, as tallow soap sets at a much higher temperature. The 
glycerin used for light colored goods must be perfectly colorless, 
but for the darker soaps this is not necessary, all that is neces¬ 
sary is that it should be free from lime and of known concentra¬ 
tion so that the quantity used may be uniform. 

To prevent cloudiness and spots, care must be taken that all spots from nme. 
the materials used be free from lime. According to circum¬ 
stances, lime may occur in the sugar, in the glycerin, and in the 
water, so that any one of these ingredients may be the cause of 
cloudiness, through the formation of lime soap. Sugar of a 
coarse grain is made from thinner solutions than small grained 
sugar, and therefore less liable to contain lime; that found on 
the market bearing the mark “Mould A” will very rarely give 
cause for complaint. 

Glycerin likewise may contain lime and other salts, in which 
case the same trouble results. If the presence of lime is sus¬ 
pected in glycerin, it may be removed by warming the latter 
slightly, adding 1 lb. of 26° B. sal soda solution to 40 lbs. of 
glycerin, stirring well and resting. 

The water used for dissolving the sugar should also be free 
from lime, and if condensed steam is not at hand for the purpose, 
the water should be first boiled and treated with soda as just 
described for glycerin. 

If the lye contains too much of foreign salts, especially of Lve 
sal soda, the soap will lose much in transparency on aging, and 
will effloresce; the lye is therefore best made of the highest 
grade of caustic, and must of course be clarified by resting, just 
as has already been described for making lye to be used for the 
cold process. As to the quantity needed, variations in the stock 
are such that a formula which gives perfect results at one time, 
may fail to do so the next time, even with the most exact weigh¬ 
ing. It is therefore necessary to watch the soap in this respect; 
when lye is lacking the soap not only is turbid, but may separate 
in the frame. 


362 


Special Soaps. 


The alcohol, especially for light colored soaps, should be free 
from fusel oil, which turns dark in contact with lye. Care must, 
of course, also be taken to use the alcohol of uniform strength, 
or to allow for variations ; the formulas following’ refer to 96 
per cent, alcohol. 

Apart from impure materials, failures in making- transpar¬ 
ent soap are g-enerally the result of incomplete saponification, of 
an excess or a lack of strength, or of too small a proportion of 
liquid in the soap; a certain amount of the latter being required 
to produce transparency in the first place, even though it may 
dry out later; on the other hand an excess of water may also be 
the cause of turbidity. To make a good article, the saponifica¬ 
tion should be as thorough as possible and the soap be finished 
neutral before adding the sugar. For this reason half-boiled 
soaps to which the filling is not added until the soap is uniform¬ 
ly developed, will always be better than those made by simply 
crutching the materials together. For light colored soaps the 

Discoloration by SU g- ar should not be exposed to a high temperature for the furth¬ 
er reason that it would thereby become colored dark yellow to 
brown. 

* For making a batch of transparent soap the stock is either 

saponified at a temperature of about 120° F.—the alcohol having 
been mixed with the lye before adding them to the stock, and the 
filling (sugar, etc.,) being added afterward—or the soap is 
made by the ordinary process of half-boiling and the alcohol, 
etc., added at the close of the saponification. The first-men¬ 
tioned method is the quickest and most economical, but the latter 
forms a noticeably clearer and lighter-colored product, which is 
more completely saponified, and will therefore keep longer. Gen¬ 
erally speaking, larger batches turn out better than small ones, 
especially as they can be kept at rest for a time when a consider¬ 
able proportion of impurities settle out. 

As already stated, the alcohol for transparent soap made by 
one or the other of these processes is common^ substituted in 
part by sugar dissolved in water; as the water evaporates and 
thereby causes the soap to shrink, the smallest necessary amount 
of it should be used only, and for strictly first-class goods it is 
omitted altogether—glycerin taking its place. The sugar is dis¬ 
solved in a little water or in the glycerin by the help of open 
steam and added to the soap. When the soap is made by mixing 
the lye and alcohol before saponification, the filling is not 


Special Soaps. 


363 


added until a sample of the soap itself remains transparent after 
it is dropped on a piece of glass and has become cold and set. If 
the sample shows a milkiness, beginning from the edge , and on 
pressure of the finger splits up in numerous small, sharp-edged 
pieces and has more or less cloudy spots distributed over the 
whole surface, it is a sign that the soap is too strong; a little 
stock must then be added, for which purpose castor oil is pre¬ 
ferred, as it is least likely to injure the transparency in case any 
unsaponified particles should remain. Powdered W. G. Rosin 
has been similarly employed, but makes the soap softer. 

But if the sample is milky, feels greasy and soft, and under 
pressure of the finger merely flattens out instead of breaking up 
into small pieces, it is a sign that the soap is too weak, and a 
little lye—diluted with boiling water to about 20° B.—will rem¬ 
edy the wrong. 

If the sample on glass shows a fine network of clouds, and 
on cooling has the appearance just described of a soap that is 
too strong, and a heavy foam covers the soap in the kettle, more 
liquid—glycerin or water—is required. 

The colors for these soaps must be soluble in water or alco¬ 
hol, insoluble colors destroying the transparency. For further 
detailson this pointsee the chapter on “Coloring and Perfuming.” 

In cutting and pressingtransparent soap it should be remem¬ 
bered that the longer it is left to dry before and after cutting up 
the frame, the better will it press. Those made without alco¬ 
hol will increase in transparency after a time. The cakes must 
be cut as nearly as possible to shape, as the soap will crack if it 
is attempted to force it in this respect. Oval cakes are for this 
reason made by running the soap warm into tin tubes, in which 
it sets and from which it is removed by pushing it out by any 
convenient contrivance. The tubes conform in shape to that 
which the cakes are intended to have, and a bar of soap is thus 
obtained from which the single cakes are cut off. For filling 
these tubes the soap, after settling, is dipped over into a jacketed 
kettle, from which it may be drawn off by means of a thin hose 
or pipe near the bottom. The lower end of the tubes is first 
plugged by means of hard soap. In drying the cakes care is re¬ 
quired to prevent over-heating which easily dims the soap. 

For the purpose of settling out the impurities contained in 
every soap, it is convenient to use a vessel, which may be sus¬ 
pended in a water bath (as in water contained in a jacket ket- 


Cutting and press 
ing. 


Moulding. 


364 


Special Soaps. 


tie), so that the clear soap may be poured off without mixing 
with it the precipitated impurities. 

Following- are a number of representative formulas for vari¬ 
ous transparent soaps. 

Crystal Transparent Soap. 

140 lbs. Cochin cocoanut oil. 

60 “ Stearic acid. 

80 “ Glycerin. 

99 “ Lye, 39 B. 

90 “ Alcohol. 

Or, 

120 lbs. Cocoanut oil. 

60 “ Stearin. 

60 Glycerin. 

60 “ Alcohol. 

90 “ Lye, 38 B. 

Mix the stock and the g-lycerin, heat to 120° F. and saponify 
by half-boiling-, finishing- the soap neutral. When the stock is 
well saponified, add the alcohol and raise the heat to 160° F. if 
the soap then is not neutral, add a few ounces of lye, or of stea¬ 
ric acid, as required, until the appearance indicates that it is 
correctly finished—according- to the signs described in the fore¬ 
going General Remarks. The soap is allowed to rest and cool 
when it is dipped over into small frames or moulds. If framed 
too warm it might have a mottled appearance. 

Glycerin Transparent Soap. 

80 lbs. cocoanut oil. 

80 “ tallow. 

50 “ glycerin. 

85 “ alcohol. 

80 “ lye, 38° B. 

The stock and the glycerin are mixed and brought to a tem¬ 
perature of 120 F., when the alcohol and lye.previously mixed, 
are run in. When the stock is well saponified, rest for two or 
three hours and add the color and perfume. The color may be 
burnt sugar or some aniline color that dissolves clear. If a light 
colored soap is wanted, half-boil the soap and add the alcohol 
afterwards. 


Special Soaps. 


365 


Transparent Soap with Sugar. 

100 lbs. cocoanut oil. 

100 “ tallow. 

118 “ lye, 35^2° B. 

90 “ alcohol. 

25 “ glycerin. 

40 “ sugar, dissolved in sufficient water to just dissolve it. 

Or, 

44 lbs. cocoanut oil. 

44 “ tallow. 

26 “ castor oil. 

57 “ soda lye 38" B. 

40 “ alcohol. 

38 “ glycerin. 

20 “ sugar, dissolved in 6-lbs. water. 

Or, 

37 lbs. cocoanut oil. 

75 “ tallow. 

56 “ 38° B. lye. 

45 “ qlcohol. 

56 “ glycerin. 

22 “ sugar, dissolved in 7 lbs. water. 

The stock is saponified and the soap finished as described 
under General Remarks. The sugar solution is added when the 
soap is otherwise finished. After settling and cooling somewhat, 
perfume and color are added and the soap framed. 


Transparent Soap with Rosin and Sugar. 

100 lbs. tallow. 

50 “ cocoanut oil. 

50 “ W. G. rosin. 

105 “ lye 38° B. 

90 “ alcohol. 

60 “ sugar, dissolved in 50 lbs. water. 

Make the soap as previously directed, by half-boiling. Then 
add the sugar solution and settle for four to five hours. Color and 
perfume the clear soap in a separate vessel. 


366 


Special Soaps. 


Transparent Soap without Alcohol. 

40 lbs. cocoanut oil. 
tallow, 
castor oil. 
glycerin, 
sal soda, 
soda lye 30° B. 

sugar, dissolved in 45 lbs. water. 


45 

50 

5 

15 

81 

40 


11 


4 L 


4 4 


4 4 


4 4 


4 4 


Or, 

48 lbs. tallow. 


42 

50 

85 

40 

10 

16-20 


4 4 


4 4 


4 4 


4 4 


4 4 


4 4 


Cochin cocoanut oil. 
castor oil. 
lye 35° B. 

sugar, dissolved in 40 lbs. water, 
glycerin, 
sal soda. 

Make the soap by half-boiling and finish it neutral, as pre¬ 
viously described. Then add the sugar solution and enough of 
the sal soda to harden. The solutions should be of about the 
same temperature as the soap. The sal soda is added in form 
of a fine powder. 

Transparent Soap Without Glycerin. 

70 lbs. cocoanut oil. 

50 
20 
70 
28 
54 


4 4 


4 4 


4 4 


4 4 


4 4 


tallow, 
castor oil. 
soda lye 38° B. 
alcohol. 

sugar, dissolved in 30 lbs. water. 

Bye and alcohol are crutched into the fats at 190 F., fol¬ 
lowed closely by the sugar dissolved in the water which has been 
heated also to 190 F. Then crutch for half an hour longer, 
color, perfume, and frame. 

Transparent Soaps Filled with Salts. 

For filling transparent soap, a solution is made of 6 parts of 
salt and 5 parts of potash in boiling water; 10 parts sugar are then 
added, and when all is dissolved enough cold water is used till 
the solution marks 22° B. while warm. The solution is settled 
and the clear part drawn off and crutched into the soap at 165° F. 


Special Soaps. 


367 


Following’ is a suitable formula: 

40 lbs. cocoanut oil. 

20 “ stearic acid. 

10 “ castor oil. 

36 “ lye 38° B. 

14 “ glycerin. 

20 “ alcohol. 

40 “ solution as above. 
Or, 

Use any of the following* compositions: 


cocoanut oil, 

26 lbs. 

24 lbs. 

36 lbs. 

tallow, 

24 “ 

27 “ 

25 “ 

castor oil, 

10 “ 

24 “ 

39 “ 

lye, 

32 “ 

40 “ 

55 “ 


(36° B.) 

(38° B.) 

(36° B.) 

glycerin, 

12 lbs. 

12 lbs. 


sugar, 

40 “ 

22 >4 “ 

20 lbs. 

water, 

30 “ 

22 Yi “ 

22 “ 

filling, 

30*“ 

4^f“ 

4J “ 

alcohol, 

— 

7 % “ 

8 “ 


*Made by dissolving in water to 15° B. equal parts of salt, 
sal soda, and potash. 

■("Consisting of 16° potash solution in which are dissolved also 
4 lbs. of sal soda. 

^Consisting of sal soda which are dissolved in the water 
called for by the formula. 

SHAVING SOAP. V 

The manufacture of shaving soap has come to be a specialty 
with certain manufacturers, whose trade in the same is sufficient¬ 
ly large to warrant them in giving this soap that attention which 
is required for the production of a high-class article. Although 
almost any soap may be pressed into service for shaving, there are 
certain requirements which determine the fitness, and thereby the 
popularity of any given brand. These requirements may be sum¬ 
med up as follows: The soap must yield a strong, thick lather— 
which should soften the hair and remain as long as possible 
without drying; it must be mild in use, and must keep a long 
time without turning rancid; in addition an agreeable odor and 
a nice white color are desirable, and it should be economical 


in use. 


Special Soaps. 


368 


To make a soap of the characteristics mentioned, great care 
and the best of materials are required. The stock most suitable 
is clean, hard, fresh beef tallow of the best quality and about 10 
to 20 per cent of cocoanut oil. For boiled soap the use of some 
oleic acid with the tallow also serves the purpose of making a 
more soluble soap. The lye used is partly potash (say three parts 
soda lye and one part potash lye). Too large a proportion of 
cocoanut oil causes the froth to dry up rapidly and fails to render 
the hair soft enough for shaving; the potash lye causes the soap 
to ’}ueld a better lather than a pure soda soap, as it produces the 
froth more rapidly, while a soap made entirely with soda lye 
yields a poor lather—which is slimy rather than frothy. For 
the further improvement of the soap, an addition of gum traga- 
canth is often made, which serves to bind the soap together and 
also makes it very mild in use, and improves the lathering qual¬ 
ities. Bassorin, a constituent part of some gums and gum rosins, 
has been used in the same way. The gum tragacanth is incor¬ 
porated with some of the hot fat, when the soap is made by the 
cold process. From 1 to 2 lbs. of the powdered gum to a frame 
will make a noticeable improvement. It may also be added to the 
soap by milling it in, as in the manufacture of toilet soaps. 

Cold-Made Shaving Soap. 

* 

It would seem that for making a shaving soap the cold pro¬ 
cess is less adapted than for any other soap; still, many people 
are blessed with a skin that is far less sensitive than that of 
others, and so it happens that cold-made shaving soap also 
finds some buyers. 

400 lbs. tallow. 

50 “ cocoanut oil. 

200 “ soda lye, 38 B. 

25 “ potash lye, 38 B. 

An improvement results if in this formula the lye is diluted 
with water to about 35° B. 




Or, 

350 

lbs. 

tallow. 

50 

< < 

lard. 

100 

11 

cocoanut oil. 

220 

11 

soda lye, 37^ B. 

60 

< i 

potash lye, 32° B. 




Special Soaps. 


369 


Or, 

300 lbs. tallow. 

40 “ cocoanut oil. 

150 “ soda lye, 37° B. 

24 “ potash lye, 33° B. 

The stock is melted and strained and allowed to cool to 100° 
F., when the lye (previously mixed) is added—as more fully de¬ 
scribed in the chapter on the cold process. The soap is lightly 
perfumed with a composition somewhat as follows: 


Oil lavender. 

.15 

parts. 

“ geranium. 

.3 


“ caraway .. 

.10 

4 4 

Oil lavender. 

.15 

parts. 

“ thyme. .. 

.10 

44 

“ caraway. 

. 8 

4 4 

“ bergamot . 

.2 

4 4 

Oil lavender. 

. 8 

parts. 

“ sassafras . 

. 6 

4 4 

“ citronella. 

. 4 

4 4 


If gum tragacanth is to be added, it is previously mixed in 
some hot fat, taking care to get out all the lumps, and added to 
the stock in crutching. Of course, enough lye for the additional 
stock so used must be added. 

Half-Boiled Shaving Soap. 

For making shaving soap by half-boiling the above formulas 
for the cold process may be adopted, using only a slightly high¬ 
er proportion of lye, as the combination of the materials is more 
complete. The formula given for a white soap, in the chapter 
on the half-boiling process, page 262, is also suitable for a shav¬ 
ing soap. The method of operating has been described in the 
same place. 

We append one more formula: 

200 lbs. tallow. 

40 “ cocoanut oil. 

130 “ soda lye 30° B. 

25 “ potash lye 30° B. 

Boiled Shaving Soap. 

As a soap made’partly with potash cannot be grained with 












370 


Special Soaps. 


salt without losing - most of the improvement in its character 
which is conferred on it by the use of this alkali, it is necessary 
to proceed somewhat differently than in the ordinary manner of 
boiling - . The stock, selected as stated before, may be saponified 
with a mixture of 3 parts soda and 1 part potash lye of about 25° 
B. until it tastes slightl} 7 sharp, and boiled to evaporate any ex¬ 
cess of water. Any small excess of strength present is then 
removed by working - in carefully a small proportion of cocoanut 
oil. This soap will, of course, contain all the glycerin formed, 
just like that made by the cold process or by half-boiling. Again, 
the tallow may be saponified alone with soda lye, grained care¬ 
fully on salt or strong lye, and settled well. After drawing off 
the waste lye, the potash lye and then the cocoanut oil are sdded, 
boiled till thoroughly combined, and either finished as before, or 
a settled soap is made. 

A more expensive, though still better product is obtained 
when the potash lye only is used throughout, the soap obtained 
by saponifying a fat with potash being changed into hard soda 
soap of especially fine grain and consistency by the subsequent 
graining on salt. 

Antiseptic Shaving Soap. 

For an antiseptic shaving soap it has been recommended to 
add 30 lbs. of salol in powder to every 1,000 pounds of soap 
while the latter is still hot. Salol, one of the most important of 
modern antiseptics, has been found effective in those species of 
skin diseases most apt to be transmitted in the act of shaving by 
barbers. Formerly shaving soap was often milled, but at the 
present time it is generally either cut square and pressed in round 
dies, or the round cakes, in which form it is sold, are punched 
out of the slabs. 


PERFUMING. 

Formulas for suitable perfumes for boiled shaving soap may 
be found in the chapter on “coloring and perfuming.” 

TOOTH SOAP. 

For the preservation of the teeth, it is admitted by dentists, 
nothing is better adapted than the free use of pure soap and a 
tooth brush. The innumerable preparations on the market, 
whether liquid, powdered, or in form of a cake, and especially 
the better ones, nearly always contain soap as the most valuable 


Special Soaps. 


371 


ingredient, and whatever else they contain, such as flavoring 
material, preservatives, etc., are only incidental additions of se¬ 
condary importance, and sometimes even of only doubtful value. 

The best means of caring for the teeth are a well-made,neu¬ 
tral and thoroughly saponified soap, followed by a mouth-wash 
made by a small quantity of permanganate of potash in water, 
flavored with peppermint, spearmint, or wintergreen oil. In ad¬ 
dition to these, the occasional use of some finely powdered sub¬ 
stance is indicated, and tooth soap therefore is, or should be, the 
best quality of soap into which has been incorporated more or 
less of some impalpable and insoluble powder. The latter should 
preferably consist of precipitated chalk, which is non-gritty, and 
therefore least apt to damage the enamel of the teeth; next in 
usefulness is finely powdered pumice stone, which is used by 
dentists for polishing teeth, but should not be employed too free¬ 
ly. These two powders may also be employed together using 
only a very small proportion of pumice stone with a large amount 
of precipitated chalk. Other substances sometimes used for 
tooth soap are talc, cuttle fish bone, orris root, sugar (for im¬ 
proving the taste), glycerin (for soft or liquid preparations), 
coloring (carmine, cochineal, aniline red), and flavoring oils. 
Some preparations contain salicjdic acid, but this has been found 
to be destructive to the teeth; the same may be said of powdered 
charcoal, cream of tartar, powdered marble dust and other sub¬ 
stances for which there should be no need in a tooth soap. Pow¬ 
dered myrrh, however, may be of use for hardening the gums. 
For an antiseptic tooth soap about 20 grains of thymol may be 
added to a pound of soap. 

For flavoring the oils must be selected with reference to 
their taste; owing to their cooling and preservative effect the oils 
of peppermint, cloves, wintergreen sassafras and cassia are most 
commonly used in tooth soaps. 

The process of manufacture may be varied, but nearly all 
tooth soap is now made by milling. Many formulas have been pub¬ 
lished for making it by the cold process, but it is doubtful if any 
such crude products can really be sold; particularly are those 
formulas worthless which recommend to add the chalk to the 
stock before running in the lye, as chalk is but another name for 
carbonate of lime, whose presence in the unfinished soap causes 
the formation of lime soap. It is different when the chalk is 
added to a finished soap as it then produces no further chemical 


372 


Special Soaps. 


• action. When other powders are substituted for the chalk the 
product by the cold process may be slightly better, but it will 
still be only a crude article, unfit for the purpose at best. 

Half-boiled or remelted soap are an improvement over the 
cold process of course, but still not equal to milled soap. 

We append two formulas. 

Half-Boiled Tooth Soap. 


Tallow.35 lbs. 

Soda Lye 38°.16^ “ 

Potash l} T e 20°.2^ “ 

Chalk. 25 “ 


The stock is strained into the crutcher and saponified at a 
temperature of 165° F. with the lye which has previously been 
brought to a temperature of 100 c F; After crutching for about 
15 minutes the machine is covered up and saponification sets in 
during about one hour’s rest. The soap is then crutched very 
slowly, as more fully described in the chapter on half-boiling, 
and when it has the appearance of a finished soap the coloring 
matter and the precipitated chalk are crutched in; lastly the per¬ 
fume (say 6 parts oil peppermint and 1 of oil of clove) is worked 
in and the soap framed. 

Milled Tooth Soap. 

Neutral soap .•. . . .500 parts. 

Orris root.200 “ 

Precipitated chalk.300 “ 

(Or chalk 250, and Pumice stone or Cuttlefish bone 50 parts.) 

Glycerin, enough to make the powders into a stiff dough. 

In order to keep the glycerin in, the cakes of soap are some¬ 
times brushed over with tincture of benzoin and wrapped in tin 
foil when dry. 

For a paste, as sold in tubes, the perfum-ed soap and chalk 
are mixed with sufficient glycerin to give the desired consistency. 

SCOURING SOAPS. 

For cleaning and polishing articles by the simultaneous 
action of soap and strong friction, as for cleaning knives and 
forks, kettles, very dirty hands, etc., etc., a considerable number 
of different soaps are made which all agree in consisting of 
simple soap and as great an addition of some more or less gritty 










Special Soaps. 


373 


powder as the soap will bear. The great variety of these soaps 
is the result of the numerous different scouring- materials added, 
selected according- to the use for which the soap is principally 
intended, and the principal ones of which are: 

Pumice Stone, Silex, Sand, Tripoli (an earth consisting 
mainly of silica), Bathbrick, Hornblende Dust, Emery, Kiesel- 
g-uhr (an infusorial earth), Crocus (a form of ferric oxide), Pre¬ 
cipitated Chalk, and various clayey deposits found in numerous 
localities in more or less suitable variety. Asbestos has been 
recommended for use in soap for glassware, etc. To this list 
may be further added some special ingredients which enter some 
soaps for particular purposes, as alum, white lead, etc. As a typ¬ 
ical example of the manufacture of these soaps we may describe 
that of Sand Soap. 


Sand Soap. 

This soap may be made by the cold process, mixing the sand 
with the stock; but it is easier to make it by half-boiling, owing 
to the large quantity of sand added to it. Scraps of soap may 
also be used for it by remelting. The stock used is preferably 
cocoanut oil, as it lathers more readily than others, with a large 
addition of an inert powder, and binds the materials most solidly 
together. The quantity of sand added may be very high, but 
for a serviceable article it is best not to exceed, say, 50 per cent 
to 75 per cent of the weight of soap, which is crutched in as soon 
as the soap is otherwise ready for framing. In making the soap 
proper, weak lye of 32° to 35° B. should be used in order that 
the soap may not be too dry when cutting, and an addition of 
some mineral soap stock will be a further help to secure a smooth 
surface. The sand must be very dry when added, or the soap 
will turn out uneven and crumbly; and while running in the 
sand slowly the crutching machine should not run too fast, in 
order to prevent air from being incorporated. As it becomes 
very hard, it is, of course, necessary to cut it—with thin wire— 
as soon as cooled. 

As in all other soaps, the addition of a part potash lye is an 
improvement, also, in this soap. Perfume may be added if de¬ 
sired. 

When other substances than sand are used for these soaps 
the proceeding may be the same as above, but some manufac¬ 
turers prefer to let the powder remain in the stock over night, 


I 


374 Special Soaps. 

and then add the lye next day to this mixture. If it is desired 
to obtain only the very finest part of any powder, such as of em¬ 
ery for polishing- metal, etc., this may be done by stirring- it up 
with water, and drawing- the latter off at once when the heavier 
particles have settled, and repeating- this once or twice. The 
powder suspended in the water drawn off is allowed to settle, 
drained and dried. 

METAL POLISHING SOAP. 

There are a number of soap preparations in use for polish¬ 
ing- metals, some of which answer the purpose admirably. A 
formula for a good article of this kind is as follows: 


Soap . 480 lbs. 

Precipitated chalk. 60 “ 

White lead . 30 “ 

Jeweler’s rouge, or cream of tartar. ... 30 “ 

Magnesia. 30 “ 


The chalk, magnesia, white lead and cream of tartar must 
be in the finest powder and intimately mixed with each other, 
and are added to the soap and well crutched in, in the ordinary 
manner. 


HARNESS SOAP. 

For cleaning, oiling and blackening harness, the necessary 
ingredients required for the purpose are all combined into one 
mass, either in the form of hard bar soap, or as a semi-soft mass 
sold in boxes or jars. 

A simple hard soap of this kind is made by adding to an 
unfilled rosin soap sufficient bone black and cod liver, or neats- 
foot oil, to make a soap of the desired character. No carbonate 
of soda filling should enter into the composition of such soap. 
The oil has a preserving influence on the leather, and also main¬ 
tains the black color better than the ordinary soap. Instead of 
bone black, which contains phosphate of lime and therefore is 
apt to cause a grayish color instead of black, there may be used 
lamp black, Frankfort black, or Berlin blue. For the purpose 
of making the color adhere to the leather, glycerin, molasses, 
or a mixture of the two is sometimes added. 

The following formula furnishes an excellent product: A 
good settled soap (made of tallow, 10 per cent cocoanut oil and 






Special Soaps. 


375 


not over 10 per cent rosin) is mixed with 5 per cent of tar, 10 per 
cent of neatsfoot oil, and 6 lbs. of lamp black to 1,000 lbs. of 
soap. Naturally this soap will take a considerable time for 
drying - . 

For a soft soap of this kind, some hard soap is mixed with 
a small proportion of potash soap, say 80 of the former and 20 of 
the latter, and enoug-h water is added to produce the required 
consistency. Some unsaponified oil and a little carbonate of am¬ 
monia are also added. 


CARBOLIC SOAP. 

For use in urinals and other purposes, a soap containing 
carbolic acid is frequently employed. (See also under “Medici¬ 
nal Soap.” The process for making it is subject to the usual varia¬ 
tions, but the principal underlying it is simply to make a hard tal¬ 
low soap (which will dissolve slowly and thus waste less rapidly 
than others) and adding to it 10 to 15 par cent of carbolic acid. 
Other disinfectants, especially chloride of zinc, are used in the 
same manner to neutralize the bad odor of closets, etc. It should 
be observed that in order to retain its effectiveness, carbolic acid 
should be added only to soaps containing no free alkali, and 
although cold-made soap is usually employed for the ordinary 
grades for coarse use, it would be more to the point to use more 
thoroughly saponified soap. Owing to the dangerous character 
of strong carbolic acid, care in handling it should be enjoined 
upon all who handle it in the factory. 

RED MOTTLED CASTILE. 

For 1,000 lbs. of tallow allow 400 lbs. cocoanut oil; run the 
stock into the kettle, but reserve about 100 lbs. of the cocoanut 
oil. Also run in a few pails of water and boil; when boiling, 
run in 8 or 10° lye till paste is formed, gradually increasing the 
strength of lye to 15 and 20°. Have some strong lye (25-30°) 
handy to run in if the soap should suddenly thicken from lack of 
strength. When enough lye has been added the soap will com¬ 
mence to open and on continuing boiling for 30 or 40 minutes 
without more lye it must remain open. Finish with a flat 
grain so that it will drop the lye quickly. Finishing: Draw off 
the lye and save it for its strength. Then warm up the 100 lbs. 
of cocoanut oil previously reserved, take out 10 lbs. and mix with 
it 3 lbs. best English Vermillion and set this coloring mixture 


376 


Special Soaps. 


aside. Turn on close steam in soap kettle and slowly feed the 
cocoanut oil which will take up the strength still in the soap; the 
latter assumes a pitchy look and, when smooth, the coloring - mix¬ 
ture is poured over the soap. When scarcely any strength is per¬ 
ceptible to the taste, no more oil is added, and boiling is contin¬ 
ued for a few minutes. When the soap no longer slips off the 
paddle but drops in big flakes and looks smooth and shiny, it is 
considered done. After 10 minutes rest it is framed and covered 
up warm to assist the mottle. 

SALT-WATER SOAP. 

For use with salt water, as on board of ocean vessels, soap 
is made entirely of cocoanut oil, as that made from other stock 
is insoluble in salt water. Such a soap may be made simpty by 
saponifying cocoanut oil in the ordinary way by the cold process, 
or it may be made from 150 lbs. cocoanut oil, saponified with 
about 150 lbs. of 2V lye, and highly filled (after the manner of 
“Blue Mottled” soaps). 


TAR SOAP. 

This was one of the first, if not indeed the first of all medi¬ 
cated soaps made, it having been observed at an early time that' 
tar has an excellent effect in chronic skin diseases, being made 
water-soluble by treatment with.caustic lye or by r incorporation 
into alkaline soaps. But its popularity is perhaps principally 
due to the fact that the soap has strong detergent properties, 
being excellently adapted for use of workmen whose work is 
such as to make the cleaning of their hands more difficult than 
usual. 

A formula for this soap has already been given in the chap¬ 
ter on “half-boiling.” 

By the cold process this soap ma}^ be made—but less satis¬ 
factorily than by half-boiling—by saponifying 50 lbs. tallow and 
50 lbs. cocoanut oil with 55 lbs. of 36° lye, and, when the mater¬ 
ials have joined, adding quickly 8 lbs. or more of tar. The soap 
must be framed rapidly, as it thickens very soon. The tar, if 
only little is used, may also be dissolved in the warm stock be¬ 
fore running in the lye. 

Formerly coal tar was not infrequently used for soap, but at 
the present time pine tar, birch tar and juniper tar are in general 
use, since coal tar dirties the soap dish and towels, has a disa- 


Special Soaps. 


377 


greeable odor and has not the healing- influence possessed by 
wood tar. 

So far as disinfecting- power is concerned experiments have 
pretty conclusively demonstrated that pine tar is about twice as 
effective as is birch tar (which is poorer in the disinfectants 
kresol, g-uaiacol, &c). 

Tar oil has been employed instead of tar with g-ood success 
when the object of the soap is great cleaning- power rather 
than healing- properties, although it is said that tar oil also has 
great medicinal properties. The proportion of tar used varies 
from 5 and 10 to 20, and even as high as 40 lbs. in 100 lbs. of 
soap. Freshly cut tar soap looks brown, if a comparatively small 
proportion of it is used; but on aging it turns black, for which 
reason it is not advisable to add coloring matter too readily, even 
if a very dark color should be desired. 

GALL SOAP. 

Oxgall contains a natural soap whose power to emulsify oils 
or fats has secured it a reputation as an ingredient for soap in¬ 
tended for removing dirt from colored fabrics and brightening 
up faded colors. It is even used pure in dyeing and cleaning es¬ 
tablishments; but for occasional use in households, for removing 
spots, it is prepared in combination with soap, as it is impossible 
to preserve it otherwise. For a soap that is desired to keep well, 
it is best to prepare the gall by boiling it, and, when cooled to 
190° F., stirring in 1 lb. of acetic ether for every 20 lbs. of gall. 
After resting some time the clarified gall may be drawn off from 
the sediment; thus prepared it keeps longer and mixes better with 
the soap. According to the manner in which it is used, it may 
be added to the soap in the state just explained, or may previous¬ 
ly be boiled down to half its original weight. 

There are a great man} 7 different formulas for making this 
soap, but it would seem that a soap made and sold expressly for 
the treatment of delicate fabrics and colors ought to be the very 
best kind of soap, and entirely neutral, so that the only formula 
to use should be based on a well-boiled and finished soap. Such 
a formula would be, for instance: 

Soap.100 lbs. 

Prepared gall. 8 “ (More or less, as desired.) 

To this may be added some turpentine, borax, quillaya ex¬ 
tract, ammonia, benzine, etc., as may seem to suit the trade best. 




378 


Special Soaps. 


The last two ingredients mentioned, however, will gradually be 
lost by evaporation. This soap is generally colored green, it 
being naturally of a grayish color. 

MEDICINAL SOAP. 

A healthy skin depends principally upon a healthy condition 
of the blood and the capillary blood vessels,' and on a proper 
nerve tone, coupled with frequent ablutions to maintain the skin 
in a state of activity regarding all its functions. Washing, be¬ 
sides simply removing dead epithelial scales, impurities thrown 
out of the system, and dirt deposited on the skin from the at¬ 
mosphere or articles touched, also stimulates the skin to proper 
action through the friction incidental to washing and drying. 
Soap is therefore one of the requisites for preserving a good com¬ 
plexion, keeping the skin clean and supplied with only the neces¬ 
sary oil by removing the excess accumulated, and maintaining 
due activity of the circulation. Under ordinary circumstances a 
good toilet soap answers this purpose better than any known 
substance if used judiciously, for too frequent ablutions or the 
application of unnecessarily' large amounts of soap are not con¬ 
ducive to a healthy skin either. The skin of some people seems 
to be proof against a slight excess of alkali in a soap, but a deli¬ 
cate skin is very sensitive to it, as carbonated as well as caustic 
alkali dissolve and remove the fat contained in the outer layers 
of the skin and leave the latter dry and prone to crack; in ex¬ 
treme cases an inflamed condition of the skin may even result. 

When the skin is affected by disease, cleanliness is again one 
of the essentials for a recovery, for it is readily understood that 
-just after the disordered surface has been cleansed from all for¬ 
eign matter it is in the most favorable condition to be acted up¬ 
on by the topical remedies applied. Soaps in which the medi¬ 
caments adapted to the particular disease in question are incor¬ 
porated have long ago been found to be a not inconsiderable 
aid in treating the latter, for they furnish a, and often the, most 
convenient mode of application. The mistake should not be 
made, however, to expect impossibilities of them, and in the ma¬ 
jority of cases they should be looked upon as valuable aids rather 
than as positive cures, for in diseases affecting the blood, the 
blood vessels, or the nervous system, and outwardly showing 
their affects on the skin, any topical remedy is obviously ineffec¬ 
tive, except insomuch as it may tend to temporarily check these 


Special Soaps. 


379 


visible symptoms. A medicinal soap, properly applied, may be 
an invaluable aid in combating- a skin eruption arising- from a 
disordered dig-estive apparatus for instance, but it is not difficult 
to understand that it can no more effect a cure, when used as the 
only remedy, than it can cure the disordered stomach. 

Similarly it is not as g-enerally understood as it should be, 
that a remedy that is capable of doing g-ood, be it a medicinal 
soap or any other medicament, is also very likely to be capable 
of doing- harm if improperly used, and this is indeed true of most 
medicinal soaps. For this reason the soapmaker should consider 
himself in line with the drugg-ist rather than with the physician; 
in other words he should not prepare the true medicinal soaps 
for indiscriminate sale, but rather direct his energy to the pre¬ 
paration of soaps to be sold on the recommendation of physicians. 
It is an undeniable fact that physicians have been for a long 
time prevented from employing medicinal soaps as much as they 
otherwise would, for the sole reason that, with a few notable ex¬ 
ceptions, this class of goods has not been prepared with a due 
appreciation of what is actually required. Unna and Eichhoff, 
both widely known dermatologists, have taken great pains to 
investigate the possibilities of medicated soaps, and it is due 
largely to their efforts that some very valuable preparations of 
this kind have been widely introduced. This chapter is, in ac¬ 
cordance with the foregoing, not intended to contain directions 
for making a line of soaps to serve as cure-alls, but rather as an 
explanation of the character of the soaps used by physicians in 
the treatment of skin diseases. 

To begin then, the soaps used as vehicles for the numerous 
medicaments employed are the hard soda soap, the soft potash 
soap, and liquid soap consisting of potash soap dissolved in suf¬ 
ficient glycerin to keep it in the liquid state. The last two forms 
are coming into greater use than they were heretofore, for the 
reason that hard soap has some unavoidable disadvantages as fol¬ 
lows: It is very mild in its action (and for that very reason 
sometimes preferred); it is difficult to preserve without losing 
most or all of certain volatile or easily decomposed medicaments 
contained therein, such as carbolic acid and corrosive sublimate; 
its character is frequently changed by becoming alternately wet 
and dry. To obviate this it has recently been proposed to add the 
drugs to powdered soap which can be rapidly made into a soft 
soap by simply adding water. Each of the three classes of soap 


380 


Special Soaps. 


mentioned, hard, soft and liquid, is again divided into neutral, al¬ 
kaline and superfatted soap, so that there are nine different 
bases to serve as vehicles for the remedy proper, according* as 
circumstances require, although for the great majority of cases 
a neutral soap is preferable. 

The alkaline soaps are the most strongly effective, while a 
milder action is obtained from the neutral and the superfatted 
varieties. A further graduation is obtained by regulating the 
quantity of soap applied, by the degree of dilution with water, 
the degree of friction applied, and by the length of time the soap 
is left in contact with the diseased skin. Of course it is also 
necessary to have due regard for the properties of the drug to be 
incorporated, as alkaline soap must naturally not be used in con¬ 
nection with carbolic acid, for instance, and sublimate can be 
used only with neutral soap. 

The manufacture of a neutral hard soap has been described 
in detail in the preceding pages; this kind is the one most usually 
employed. To prevent changes in the medicaments introduced, 
the milling process is undoubtedly the most rational. 

A neutral potash soap must be made in an indirect manner, 
as a complete saponification with potash lye can be effected only 
in the presence of an excess of strength. The first step in its 
manufacture is to make a hard soda soap from the choicest fat 
or oil (olive oil) and soda. The fatty acids are next separated 
from the same b}' the addition of dilute sulphuric acid, and must 
then be washed out with distilled water until thelatter runsoff per¬ 
fectly free from any trace of the sulphuric acid. The pure fatty 
acids are then saponified with pure caustic potash, taking care 
to finish the soap perfectly neutral. The product is then boiled 
down to the proper consistency.' 

The neutral liquid soap is made in the same manner, but 
diluted to the desired consistency with pure glycerin. Its color 
approaches that of honey, it is transparent and dissolves clear in 
water and in alcohol and is of course perfect^ neutral.’ 

The alkaline liquid soap is made from the foregoing b} T the 
addition of about 4 per cent of carbonate of potash, and is an 
excellent detergent for the skin and for medical instruments. It 
is well adapted for the bath, washing the scalp and wherever 
scales and crusts are to be removed. 

The superfatted liquid soap was formerly made by the addi¬ 
tion of 3 to 4 per cent of olive oil to the neutral soap; but as this 


Special Soaps. 


381 


free fat becomes rancid in time, it is now frequently supplanted 
by the same proportion of lanolin, which keeps indefinitely and 
besides is more readily absorbed by the skin; the use of super¬ 
fatted soap was first proposed by Dr. Unna. 

The superfatted and the alkaline hard and soft soaps are 
made in like manner from the neutral soaps of their respective 
type. 

Superfatted soap, containing- an excess of neutral fat when 
first made, will not keep very long- at best, and some medica¬ 
ments have the effect of. spoiling- the soap entirely within a few 
weeks, so that lanolin or vaseline must in these cases take the 
place of the excess of oil or fat. It is hardly necessary to point 
out that, as both lanolin snd vaseline are unsaponifiable, they 
cannot of course neutralize any excess of alkali present in the 
soap; all they can do at best is to counteract the effect of such 
excess, to which action lanolin adds that of increasing-the effects 
of the medicaments by- reason of the avidity with which the skin 
absorbs the lanolin. 

The principal medicinal soaps, which have proved most 
serviceable in the hands of competent physicians, are the fol¬ 
lowing - : 

Soft Soaps: 

Tar Soap, containing- 1 to 8 drachms of tar to the ounce. 

Naphthol Soap, containing- fz to 3 drachms (or more) of 
naphthol to the ounce. 

Carbolic soap, containing- 10 to 90 grains of carbolic acid to 
the ounce. 

Salicylic Soap, containing 10 to 90 grains of calicylic acid 
to the ounce. 

Sulphur Soap, containing any desired proportion of sulphur. 

Balsam of Peru Soap, containing x /z drachm or more to the 
ounce. 

Hard Soaps: 

Alum Soap, containing 10 per cent of alum. 

Arnica Soap, containing 10 per cent of extract of arnica. 

Balsam Soap, containing 5 per cent of balsam of Peru. 

Boro-Glycerin Soap,* containing 10 per cent of a 50 per 
cent solution of boro-gl} 7 ceride. 


*Tliis soap is preferred to one simply containing boric acid or borax. 



382 


Special Soaps. 


Camphor Soap, containing- 10 per cent of camphor. 

Carbolic Soap,f containing- 5 per cent of carbolic acid. 

Chamomile Soap, containing- 10 per cent of extract of cham¬ 
omile. 

Ergot Soap, containing 10 per cent extract of ergot. 

Eucalyptol Soap, containing 5 per cent of oil of eucalyptus. 

Iodine Soap, containing 3 per cent of resublimed iodine. 

Naphthol Soap, containing 5 per cent of naphthol. 

Naphthol-Sulphur Soap, containing 3 per cent of naphthol 
and 10 per cent of sulphur. 

Salicyclic Acid Soap, containing 4 per cent salicyclic acid. 

Sublimate Soap, containing 1 per cent or 2 per cent of cor¬ 
rosive sublimate. J 

Sulphur Soap, containing 10 per cent of sulphur. 

Tar Soap, containing 10 per cent of tar. 

Tannin Soap, containing 3 per cent to 5 per cent of of tannic 
acid.§ 

Tannin-Balsam Soap, containing 2 per cent of tannic acid 
and 5 per cent of Balsam of Peru. 

Thymol Soap, containing 3 per cent or crystallized thymol. 

Witch Hazel Soap, containing 10 per cent of extract of ham- 
amelis. 

For their better preservation, medicated hard soaps are usu¬ 
ally wrapped in parchment paper or foil. 

Supperfatted Soaps: 

Aristol Soap, containing 2 per cent of aristol. 

Benzoic Soap, containing 5 per cent of benzoin. 

Creolin Soap, containing 5 per cent of creolin. 

Creosote Soap, containing 2 per cent of creosote. 

Iodoform Soap, containing 5 per cent of iodoform. 

Iodol Soap, containing 5 per cent of iodol. 

Menthol Soap, containing 5 per cent of menthol; used for 
for the anaesthetic effect on the skin, in pruritus, and 
in tooth soap; when used on the face the eyes should be 


fTlie addition of glycerin lessens tlie smell of tlie carbolic acid. Napli- 
tliol or saliev lie acid soap is often preferred to it on account of the odor. 

X Corrosive sublimate is decomposed and will discolor the soap, if free 
alkali is present. 

^Tannin soap is recommended for use in cases of excessive sw'eating of 
hands and feet. 



Special Soaps. 


383 


kept well closed, as menthol in contact with the con¬ 
junction produces a very disagreeable feeliug.of cold. 

Menthol-Eucalyptol Soap, containing 5 per cent of menthol 
and 3 per cent of oil of eucalyptus. 

Pine Needle Oil Soap, containing 10 per cent of pine needle 
oil. 

Quinine Soap, containing 5 per cent of quinine. 

Resorcin Soap, containing 5 per cent of resorcin. 

Resorcin-Salicylic Soap, containing 5 per cent of resorcin 
and 3 per cent salicylic acid. 

Resorcin-Salicylic-Sulphur Soap, containing 5 per cent of 
rescorin and 3 per cent each of sulphur and salicylic acid. 

Salol Soap, containing 5 per cent of salol; in use the salol is 
said to break up into carbolic acid and salicylic acid 
which then have a stronger action than they usually 
have. 

Salicylic-Creosote Soap, containing 5% of salicylic acid and 
2% creosote. 

Sulphur Soap, containing 10%" of sulpur. 

Sulphur-Salicylic-Tar Soap, containing 5% each of sulphur, 
salicylic acid and tar. 

Tar Soap, containing 5% of tar.* 

Thiol Soap, containing 5% and 10% of thiol. 

SULPHUR SOAP. 

Apart from the simple sulphur soap, the manufacture of 
which by various processes is sufficiently indicated in the pre¬ 
ceding pages, there may here be mentioned the attempts to bring 
the sulphur into a more effective form by special means. We refer 
to the invention patented by J. D. Riedel of Berlin, according 
to which sulphur is heated for four hours with fatty acids or fats 
of the so-called unsaturated series (red oil, linseed oil, castor oil) 
to 250-320° F. whereby a new compound “thiofat” is formed 
which is then saponified, together with an equal amount of 
cocoanut oil by lye at a low temperature, (a high temperature would 
decompose the sulphur compound again). In soap so made - 
named “thiosapol” the sulphur is chemically bound and presum- 


*Tar is frequently introduced into soaps which are medicated at the 
the same time with sulphur, salicylic acid, resorcin, &c. 



384 


Special Soaps. 


ably more effective medicinally than can be the sulphur mixed in 
only mechanically. 

To carry out this process, the result of which is a soap con¬ 
taining- 5% of sulphur, 1,000 parts of linseed oil are treated 
with 166 parts sulphur as stated; of the product 1,000 parts are 
saponified, tog-ether with 1,000 parts cocoanut oil, at a temper¬ 
ature of about 75° F., with 1,000 parts soda lye of 35% strength. 

SURGICAL SOAP. 

All soap is more or less strongly antiseptic, but in order to 
increase this quality, various additions are made, of which cor¬ 
rosive sublimate, carbolic acid, salol, thymol, &c., have already- 
been mentioned. For surgical use the following is a prescription 
emanating from a Surgeon (Prof. Reverdin of Geneva): 

Oil of sweet almond, 72 parts. 

Caustic potash lye, 12 “ 

Caustic soda lye, 24 “ 

Sulpho-carbolate of zinc, 2 “ 

Oil of rose to perfume. 

It will be noted that this soap is described as being made by 
the cold process which, especially with almond oil, is hardly to 
be recommended from a soap maker’s point of view. However, 
Dr. Frank L. James of St. Louis states that he has used for years 
a similar soap, but made with cottonseed oil instead of almond 
oil and containing more (3%) of sulpho-carbolate of zinc, to his 
entire satisfaction. 

The advantages of this soap are that it has remarkable 
cleansing and antiseptic properties, without being at all iritating 
to the skin; as the strength of the lye is not given, we will add 
that the soap is intended to be superfatted. 

Prof. Reverdin recommends this soap not only for general use 
in hospital and private practice, but also for washing the hands in 
dissecting rooms and wherever the hands come in contact with 
decomposing substances. Further, he urges that barbers should 
universally adopt its use, and thus protect their customers from 
various infectious diseases, to which they are exposed in 
their shops. 

While it is obviously best to introduce no coloring matter in¬ 
to soaps to be used for medicinal purposes, they are frequently 
perfumed, as for instance in the following formula for a 


Special Soaps. 


385 


Hipped Camphor Soap. 

100 lbs. neutral soap. 

3 “ camphor, dissolved in the required quantity of alcohol. 

Perfumed with 

Oil of cloves, 4 parts. 

“ rosemary, 5 “ 

“ lavender, 10 “ 

“ peppermint, 3 “ 

WASHING POWDER. 

Washing- powders, usually sold to the consumers as soap pow¬ 
ders, may be described in a g-eneral way as powdered mixtures of 
soap, with about its own weig-ht—more or less—of carbonate of 
soda. Some special brands are also made which in addition con¬ 
tain other deterg-ent ag-ents, such as carbonate of ammonia, sal 
ammonia, or borax, while still others are found, to which filling 
in the form of talc, silex, sulphate of soda, paraffin, etc., has been 
added. The soap itself may have been made by any of the pro¬ 
cesses known—cold, half-boiled or boiled, settled or boiled down 
—and the stock used may have been any fat, or mixture of fats, ac¬ 
cording to the grade of washing-powder to be made. It is thus 
seen that being either principally or entirely a mixture of soap 
and soda, these powders have little in common with each other, 
and the process of their manufacture—and even the machinery 
used in each case—are equally at variance in the several factor¬ 
ies, being decided upon independently and improved upon by the 
soap maker, in accordance with his own peculiar circumstances 
and experience. 

It would, therefore, be useless to publish formulas for any 
one kind of this article, as the stock available, the selling price, 
the profit intended to be made and the manufacturing facilities are 
so different that no single formula might suit more than one reader 
—if any. We will instead describe its manufacture in a manner 
that will enable the reader to work out his own formula. 

The average soap powder of the better grade, as stated above, 
consists of a soap and about a like amount of carbonate of soda, 
the latter being added either as sal soda or as a mixture of sal 
soda and soda ash. So far as the soap itself is concerned, the 
best is again one made by boiling and graining on salt, for, be¬ 
sides being more perfectly saponified, such a soap has the ad¬ 
ditional advantage of not containing the glycerin resulting from 


386 


Special Soaps. 


the saponification, and therefore remaining - drier when in the form 
of powder. Furthermore, it islighterin color and purer, owing to 
the coloring matters and other impurities removed with the waste 
lye. Rosin is scarcely admissible, or at least not in any consider¬ 
able proportion, as it would make the product sticky and difficult 
Making the soap, to reduce to the form of a powder. The stock used, say grease for 

instance, is saponified in the usual manner with soda lye, and, 
when it has a slight excess of strength, is grained on salt. The 
soap is allowed to rest, so as to drop the waste lye thoroughly 
and to cool off somewhat, and is then ready to be mixed with the 
soda, etc., unless it is intended to settle it first—as may be done 
to advantage in the manner described under “Settled Soap. 1 ’ On 
the other hand, the soap may also be boiled down, so that it will 
contain comparatively little water, in which case the carbonate of 
soda to be added may consist of more sal soda and less dry alkali. 

The mixing may be carried out in a crutcher, in flat boxes 
on the floor, or in a jacketed kettle (after drawing off the waste 
lye). If it is done in the kettle it should be one so shaped that 
the contents can be thoroughly worked by two men provided with 
hand crutchers and stationed on opposite sides of the kettle. If 
wooden boxes are used, they should be placed on the floor, of 
suitable size for mixing, and not more than say 1 Yo. feet deep, to 
permit thorough crutcliing; into these boxes alternate layers of 
soap and filling are placed and worked thorough by means of 
rakes. The easiest manner of working is undoubtedly by the 
crutching machine. 

The ingredients to be added, if consisting of several kinds, 
are best previously mixed with each other, so as to insure uni¬ 
formity of the mass. Some manufacturers use 50 lbs. of talc, or 
—which is better—silicate of soda, and 300 lbs. of sal soda to 
every 300 lbs. of soap in the crutcher, and these are thoroughly 
worked through, taking care to avoid lumps as much as possible, 
whereupon the mass is spread on the floor of the drying room 
and turned over daily by means of rakes, until dry. This 
process requires nearly a week, and has been superseded in most 
places by substituting about 100 lbs. of soda ash for the same 
amount of sal soda in the above mixture, so that the formula 


would be in this case: 

Soap.300 lbs. 

Sal soda, 36°.200—225 lbs. 

Dry alkali or soda ash. 85—100 lbs. 

Talc. 50 lbs. 






Special Soaps. 


387 


While mixing-, the soap should be kept hot, if possible, by 
admitting- steam into the jacket, and the sal soda also should be 
used hot. The effect of the soda ash is to absorb the moisture 
of the soap, thereby making- the product harder and causing- very 
quick drying-. The soda ash should be pure, so that the water 
may not be discolored by it in use. The mixture may be run into 
frames to set, and afterwards cut into bars and dried. 

After sufficient drying-, the product is passed through the 
grinding- mill, sifted and packed. For grinding-, a number of 
different machines are used, but it is necessary to guard against 
heating in the mill, to avoid melting of the soap. A simple con-, 
trivance is a revolving sheet iron drum, perforated in the manner 
of an ordinary grater, against which the soap is held by any suit¬ 
able means. The sieve should have suitable attachments for 
turning the coarse tailings back into the mill. 

From the above description, the manufacture of a soap pow¬ 
der by lialf-boiling is self-evident, so we need not go into details 
regarding it. A variation, however, may be mentioned, which 
consists in using red oil (oleic acid) as the siock, and saponify¬ 
ing it by half*boiling, or by the cold process, with caustic lye or 
a solution of carbonateof soda, using in the firstcase rather less lye 
than is required for the complete saponification. While the soap 
is still liquid the soda is added, when, in consequence of the car¬ 
bonic acid disengaged, the mass rises in a somewhat frothy, dry 
body, which is soon ready for the mill. Red oil being a fatty 
acid, it saponifies readily with carbonate of soda, and of course, 
the product is free from glycerin. In saponifying this stock the 
precaution, previously mentioned, of adding the red oil to the 
lye, instead of the reverse, must be observed, in order to prevent 
bunching of the materials. 

There is also on the market soap powder containing ammonia 
in the form of one of its salts (free ammonia would rapidly eva¬ 
porate). Such powder may have no odor of ammonia while dry, 
but develops the same rapidly when put into water, especially 
warm water. Ammonium sulphate used in the proportion of say 
5% answers the purpose. If a powder containing this salt and 
soda ash is dissolved in water, the previously combined ammonia 
is liberated and shows its presence by its odor and by its deter¬ 
gent effect, the reaction consisting first in a decomposition of the 
soap itself with setting free of caustic soda which reacts with the 
ammonium salt to form sodium sulphate and ammonia, at the 


388 


Special Soaps. 


same time the carbonate of soda in the soap powder goes to form 
sodium sulphate and carbonate of ammonia which has similar de¬ 
tergent properties as has the gas. Similarly ammonium chlor¬ 
ide behaves in soap powder, but is more difficult to work with, 
as unless the powder is dry and free from excess of caustic, it 
attracts moisture and spoils the packages; in adding this salt to 
a soap powder a high temperature must be avoided. (See App. 
Note 19). 

In concluding it should be repeated that the foregoing has re¬ 
ference to the better grades of soap powder, as it is not within 
the province of this book to go into details regarding products 
which are discreditable to the manufacturer, as an instance of 
which we will only mention one of a number of formulas which 
have been highly lauded by parties who ought to know better, 
as follows: “40 lbs. sal soda, 20 lbs. caustic soda, 15 lbs. sili¬ 
cate of soda, 2 lbs. palm oil, 20 lbs. water.” Formulas of this 
kind may be considered valuable by their fortunate possessors, 
but we do not deem them in any way connected with soap making, 
nor calculated to serve as a basis for a successful business. 

An ingenious variation, which is said to be practiced in 
some European countries, consists in boiling linseeds directly 
with caustic lye. The product is a thin linseed oil soap contain¬ 
ing more or less extractive matter which causes strong frothing 
in use, creating the impression that the amount of soap present 
is m-uch larger than it really is. 


CHAPTER XIX. 


Sal Soda flaking. 


Owing to the considerable amount of space required in the 
making of sal soda crystals, and especially to the difficulties of 
the process in warm localities in which the work can proceed on¬ 
ly for part of the year, and, lastly, owing to changes which time 
has wrought in the uses of sal soda, soda ash, washing powders, 
and kindred products, the making of this product has been dis¬ 
continued in many factories in which at one time it constituted 
a considerable part of the business. Notwithstanding, this how¬ 
ever, there are many readers for whom a description of the pro¬ 
cess still has a practical interest. 

The process consists, briefly, of making a saturated or al¬ 
most saturated hot solution of soda ash in water, with or with¬ 
out certain additions to be mentioned further on, settling, allow¬ 
ing to crystallize, and separating the crystals so gained from the 
mother liquor. 

To do this work there are required: a tank for dissolving the 
soda ash and provided with facilities for heating the contents; a 
number of crystallizing vessels, and an arrangement for drying 
the crystals obtained; also pipe connections and pumps arranged 
according to circumstances. 

For dissolving the soda ash a large tank is needed, preferab¬ 
ly one arranged with an open steam coil at the bottom, and over¬ 
hung by a perforated iron basket (sieve) into which the alkali 
can be thrown so as to be just suspended in the water contained 
in the tank. A tank of this kind has already been described in 
the paragraph treating on lye-tanks, and should be provided with 
the same valves, &c., as there stated. It is almost needless to 




390 


Sal Soda Making. 


say that such a tank must be kept ver} 7 clean, especially from 
rust. 

The crystallizing- vessels may be of many different sizes, 
shapes, and materials; they are used in sizes rang-ing- from 200 
to 3,500 lbs. capacity, cylindrical, square or cone shaped, of 
cast iron, wrought iron, sheet iron riveted, enameled or not en¬ 
ameled, hig-h or rather flat, &c. A convenient shape is 16 x 10 
feet and 2 feet deep. The principal difference is in the fact that 
in a large vessel the crystallization proceeds more slowly, es¬ 
pecially in warm weather, but yields larg-er and more beautiful 
crystals. Convenience in the removal of the crystals is another 
consideration; as to the material of which they are made, the 
most economical among- those named is as g*ood as any other, if 
kept properly cleaned, and old tanks of various kinds are some¬ 
times pressed into service. If of larg-e size, they are best speci¬ 
ally arrang-ed so as to be easily tilted over, and with walls slant¬ 
ing-, so that (after previously heating-the walls slightly by steam) 
the whole contents can be discharged readily by merely tipping 
the vessel. These vessels are filled nearly to the brim and if 
they are of large size the crystallization may be hurried by la} 7 - 
ing across the top a number of iron rods about a foot apart so as 
to touch the surface of the solution at different points; it is at 
these points where the first crystals form, whereupon the process 
spreads rapidly throughout the solution; from these rods smaller 
ones are sometimes suspended, dipping half-way into the solu¬ 
tion. As a rusting of the vessels gives a yellowish tint to the 
crystals, it is necessary to prevent it by not having them empty 
any longer than can be helped at any time. 

The Solution. 

Water: Hard water is preferred for this purpose, as with its 
use a smaller proportion of sulphate of soda is needed (and much 
of the latter would retard the crystallization). 

Soda Ash and additions: A high grade soda ash yields small, 
soft crystals which moreover retain much of the colored mother 
liquor; instead of using it pure, therefore, an addition of from 3 
to 8 per cent of calcined sodium sulphate (Glauber’s Salt)—more 
or less according to the water used is hard or soft—is taken ad¬ 
vantage of in order to obtain beautiful, hard crystals. It is to 
be remembered, however, that the Glauber’s salt acts chiefly by 
its mere presence in the solution and does not actuall) 7 enter into 


Sal Soda Making. 


391 


the crystals in nearly as large a proportion as it is present in the 
liquor; on an average the crystals made with its help contain 
about 2 per cent of Glauber’s salt; the remaining - mother liquor 
being - so much richer in it, of course, this is a feature to be con¬ 
sidered also when the latter is used over ag - ain for the next 
batch. 

For the purpose of obtaining - clear crystals another addition 
is made, namely of a very small proportion of chloride of lime. 
Thus a suitable mixture would be, for a water of average hard¬ 
ness: 97 per cent soda ash, 2.4 per cent anhydrous sulphate of 
soda (or correspondingly more if the crystals of Glauber’s salt 
are used), and 0.1 per cent chloride of lime. 

Yield : Such a mixture is expected to yield 200 per cent of actual 
crystals and 60 percent further which remain in the mother liqu¬ 
or at first and are obtained from it on the next batch. In hot 
weather, however, a smaller yield may result from one or two 
causes: for one thing, too much soda may remain in the mother 
liquor and the loss is then one of working expenses; but on the 
other hand crystals may form which contain 25 per cent less than 
their due proportion of water, in which case the crystals turned 
out are richer in alkali than was intended. (34-37 per cent). 
(See also Appendix, note 17). 

Soda ash colored by iron oxide can be used without detri¬ 
ment, as the iron oxide remains behind in the solution. 

Making the Solution: Roughly figured, one part of soda ash 
requires two of water; the solution should be made with hot wa¬ 
ter, although actual boiling is of no advantage and merely wastes 
time in clarifying. It is regulated to be an almost saturated 
solution, indicating 31° Baume while hot, (33° when cold), but 
in hot weather it requires the strongest solutions (fully 34° B. 
cold) to crystallize at all. The same method of dissolving, ow¬ 
ing to the caking properties of soda ash, is followed as described 
under the preparation of lyes, i. e., the soda ash is placed on a 
strong wire sieve just immersed in the water. When all is dis¬ 
solved a rest is allowed for settling, requiring say 10-18 hours 
during which the solution cools off to 145-165° F.,at which tem¬ 
perature (no more settling taking place) it is run into the cryst¬ 
allizing vessels. Instead of settling a filterpress may be used. 
The sediment in the settling tank is washed for the soda in it, 
before throwing away. 


392 


Sal Soda Making. 


Crystallizing, etc. 

In the vessels already described, if the weather be cool, com¬ 
plete crystallization will require about a week—more or less as 
to size of vessels—but in warm weather it proceeds slowly, re¬ 
quiring- twice as long- as perhaps as in winter, and even then the 
yield is smaller, as already pointed out; in very hot climates the 
manufacture is indeed practically impossible, and in very larg-e 
plants artificial cooling- has in some instances been resorted to. 
The completion of the process is recognized by examining the 
condition of the crystals and measuring the mother liquor with 
the lye scale; it should indicate 20-22° B. when all the crystals 
possible or formed. 

The mother liquor is then removed by suitable means (tipp¬ 
ing the vessels or pumping), when the crystals will be found 
firmly adhering to the walls of the vessels and require loosening 
by the application of heat, which is carried out again according 
to circumstances, i. e. by hot water, steam, or by main force; for 
small vessels a hot water bath is sometimes the most conven¬ 
ient method. After loosening the crystals are drained b} r placing 
them on a slanting floor and then dried further by either exposing 
them to the atmosphere or—a much m'ore rapid method—by use 
of the centrifuge, which dries them almost perfectly. They are 
then stored in a cool, dry place, protected from draft, so that 
they will neither attract moisture nor dry out. 

The remaining mother liquor is used again for the next 
batch, until finally it becomes so discolored that the crystals be¬ 
come affected thereby; with the use of chloride of lime and high 
grade soda ash as described, however, the mother liquor can be 
used over almost indefinitely by simply collecting it in the tank 
for making the solution and adding fresh soda ash and water and 
then proceeding as before. When it gets altogether too dark, 
requiring an amount of bleach that gives its odor to the pro¬ 
ducts, it is perhaps possible to use it up for a low grade of soap. 
It is also convenient to use for keeping the crystallizing vessels 
filled while they are out of use in hot weather. 


PART V. 








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CHAPTER XX. 


Glycerin and Its Recovery from Waste Lye. 


In the year 1779 Scheele, a celebrated Swedish chemist of 
his time, observed that in saponifying olive oil with oxide of 
lead, the washings contained a sweet substance which he term¬ 
ed “fat sugar” or “oil-sweet.” The real character of this 
substance (glycerin) was disclosed by the researches of Chevreul 
who in 1824 proved fats and oils to be compounds which in the 
• process of saponification split up into fatty acids and glycerin, 
absorbing the elements of water in doing so. (See App. Note 2). 
Since that time the production and utilization of this substance 
have grown apace. Price’s Patent Candle Company was the first 
to put on the market a commercially pure glycerin derived from 
its bye-product in large quantities. 

Separated and purified, glycerin has gained an immense field 
of usefulness in the comparatively short time since its discovery. 
Its employment in soap itself has already been sufficiently set 
forth; in the manufacture of various cosmetics and in pharmacy 
it finds a still more extensive use; enormous quantities find an 
outlet in the manufacture of nitro-glycerin and dynamite, and 
finally its high boiling point, affinity for water, solvent power, 
and its other properties, have secured it a field of great useful¬ 
ness in various industries. Thus in the textile industry large 
quantities are needed to give suppleness to the thread or to the 
goods in various stages of their manufacture its great advant¬ 
age for this purpose lying in the fact that simple water readily 
removes the glycerin again when it is no longer needed. In the 
fur and leather industries it finds somewhat similar employment. 
In liquid glues, hektograph compositions, printers’ rollers, print- 




396 Glycerin and Its Recovery from Waste Lye. 

ing and copying- inks, colors, certain kinds of paper, and a great 
many other articles, it finds useful employment. As a result of 
these many uses, glycerin has a market value which has made 
the recovery from waste lye remunerative, and whereas formerly 
waste lye was universally run away—the glycerin needed being 
obtained nearly altogether from candle factories—it is now a very 
general practice in the large soap factories to work up the waste 
lye for its glycerin. 

There are, accordingly, these two great sources of the gly¬ 
cerin of commerce at the present time: 1. Waste lye of the soap 
factory; 2. From candle factories, as by-product in the manu¬ 
facture of fatty acids from fats and oils for candle making; this 
production of fatty acids for candles is done in various ways 
which fall into two large groups,namely a) subjection of the fat 
to 9 to 10 atmospheres of steam pressure in a closed vessel (with 
or without a few per cent of lime or magnesia being added to the 
fat), or b) adding concentrated sulphuric acid to the fat heating 
with water, and distilling off the fatty acids in a current of super¬ 
heated steam; in the latter process of “acid saponification” or 
“distillation,” the glycerin (which is contained in the “sweet 
water” which also comes over but separates from the fatty acids) 
is less pure than when the saponification is carried out by simple 
steam and pressure. 

The glycerin from all these sources is further purified by 
various means adapted to the nature of the crude product obtain¬ 
ed, so that there are the following chief divisions: 

A. Crude: 

1) From soapmakcrs ’ lye; the least pure, generally speaking. 

2) Saponified , (from fats treated with steam under pres¬ 

sure); the purest, generally speaking. 

3) From distillation , i. e. obtained from fat by acid saponi¬ 

fication and subsequent distilling; in quality inter¬ 
mediate between the foregoing two. 

B. Purified: 

1) Refined , still containing chlorides, sulphates, &c., but 

sufficiently pure for most purposes. 

2) Dynamite glycerin: distilled, but not chemically pure, 

still containing traces of chlorine and various empy- 
reumatic substances. 

3) Distilled, chemically pure, for use in medicines, &c. 


Glycerin and Its Recovery from Waste Lye. 397 


The amount of glycerin theoretically yielded by different 
fats and oils ranges from 9.13% castor oil to 10% for tallow and 
12.11% for cocoanut oil; but the full amount is never recovered 
in actual practice. The different percentage depends on the dif¬ 
ferent combining value of stearin, olein, palmitin, myristin, etc. 

In a series of tests made of cases in actual practice in a 
French factory there were recovered the following amounts of 


crude glycerin: From Olive Oil, 

7-9% 

Peanut Oil, 

6-7% 

Cotton “ 

7—9% 

Palm “ 

5-10% 

Palmkernel Oil, 

6—10% 

! Cocoanut “ 

7-8% 

Tallow “ 

9—10% 


The crude glycerin in question contained about 80% of the 
pure article, some of which however is lost in recovering it. 

When pure glycerin is a water white, very viscid fluid, sp. 
gr. 1.266; so that commercial glycerin usually has a sp. gr. of 
about 1.260 to 1.264 it has a sweet taste and rapidly absorbs 
moisture from the atmosphere; it is soluble in alcohol, but only 
very slightly soluble in ether and insoluble in chloroform and 
benzine; chemically it belongs to the group of alcohols. Strictly 
speaking it is not present ready-formed in neutral fats and oils; 
what is present in these is “glyceryl” which, during saponifica¬ 
tion, absorbs oxygen and hydrogen and becomes glycerin. Ow¬ 
ing to its power of dissolving considerable amounts of salts and 
organic impurities its purification is a somewhatdifficult problem. 

RECOVERY FROM WASTE LYE. 

When neutral fats have been boiled with lye and the fatty acids 
have combined with the alkali, and the soap has been grained with 
salt or lye, glycerin is found dissolved in the waste lye. Of course 
no glycerin could be obtained from treating fatty acids (e.g. red 
oil, rosin) with lye, and the lye from the first change alone con¬ 
tains considerable amounts of the glycerin resulting from treat¬ 
ing neutral fats with lye. What glycerin is not taken out in this lye 
finds its way mostly into the strengthening lye, and (as this is 
saved for the next batch;, is recovered after the strengthening 
lye has been used over to kill stock for the next batch. 

A waste lye contains therefore chiefly water with very vari¬ 
able amounts, according to circumstances, of glycerin, caustic, 


398 ' Glycerin and Its Recovery from Waste Lye. 

carbonate, salt, soap, glue, and other impurities of animal or 
vegetable origin. As these variations effect the success of re¬ 
covering the glycerin, both as to cost and quality,they require con¬ 
sideration as early as the first change of soapmaking. The 
weaker the lye, the more thoroughly will it extract the glycerin, 
which more than offsets the greater amount of water to be eva¬ 
porated. Another early consideration is the graining of the 
soap at the end of the first change: one may grain with salt and 
directly work up the waste lye which on an average will contain 
about b% glycerin and say 9 % of salt, or the soap at the end of 
the first change may be grained with lye and the waste lye used 
for another batch, and so on till the lye is heavily charged with 
glycerin; by then graining with salt a waste lye is obtained 
which not only requires a minimum of evaporation for a given 
amount of glycerin, but also gives the least possible amount of 
salt precipitating during the evaporation. To what extent these 
considerations can be used to advantage will depend largely on 
the quality of the stock used. Again, after graining, an extra 
pickle change may be given in order to more thoroughly wash 
out the glycerin; whether or not this will pay depends on the 
facilities for evaporating the excessive water economically and 
on the more or less advantageous disposal of the additional gly¬ 
cerin so recovered. 

In its main features the process for crude glycerin recovery 
consists, first of a preliminary cleaning, then evaporating a con¬ 
siderable portion of the water whereby a large portion of the salts 
is thrown out of solution by reason of the concentration; this salt 
is removed and an acid is added to the lye for the purpose of de¬ 
composing remnants of soap and precipitating with it incidentally 
some of the other impurities; after taking off this precipitate of 
fatty acids, &c., the lye can be still further boiled down and some 
more salt removed. When a specific gravity of about 1.3 is reached 
a crude glycerin is the result. This is purified further by distil¬ 
lation, etc. From this general principle, which was the basis of 
the first attempts at glycerin recovery, a number of variations 
have in the course of time been devised, having in view the re¬ 
moval of certain other (chiefly organic) impurities present in 
waste lyes of varying origin and character; these variations em¬ 
brace chiefly filtration, addition of chemicals adapted to the 
removal of special impurities, and mechanical appliances, for 
economical evaporation, removal of salt, &c., not to speak of a 


Glycerin and Its Recovery from Waste Lye. 399 


patent for purifying- the lye by electricity, these inventions have 
grown out, by proper selection and combination of suitable fea¬ 
tures, a system of glycerin recovery that has found very extensive 
use and which has made it possible at the present time to make 
from waste lye the chemically pure article answering the strictest 
requirements of the pharmacopia, whereas only a few years ago 
it was not possible to do better than to make the dynamite grade 
of glycerin from waste lye. 

In the course of the line of treatment so briefly indicated 
just now, which waste lye must undergo, there arise some prac¬ 
tical problems and difficulties whose solution in the most practi¬ 
cal manner will probably always determine the precise methods 
of glycerin recovery that will survive. Thus on boiling down 
the lye, the increasing concentration involves also the impurities 
present, and at the same time the more concentrated glycerin 
has a greater solvent power, so that previously suspended im¬ 
purities now become actually dissolved and the glycerin corres¬ 
pondingly more impure. The removal of impurities in the early 
steps of the process is therefore one of the great desiderata. At 
the same time each particular means adopted for this early re¬ 
moval brings its own problems. Then again, as the lye is more 
and more concentrated, an increasing amount of salt is precipit¬ 
ated and this must be disposed of in such a way that it cannot 
interfere with the heating surface of the apparatus and thereby 
interrupt the work. Chemicals used for precipitating impurities 
must be of a nature to either deposit before concentration, or if 
they remain they must be incapable on concentration to do any 
harm (as for instance sulphuric acid would carbonize certain im¬ 
purities on becoming concentrated, &c.) 

Owing to the manipulations necessary for the rational treat¬ 
ment of lyes, before a pure glycerin is obtained, it is only the 
larg-e soap factories that carry out the entire process, smaller 
factories which have only a limited amount of lye to work up 
limiting their work to the production of crude glycerin or even 
to simply concentrating their lye for the saving of freight on the 
water removed by evaporation, and shipping their product to the 
refinery. The process then is divisible into the two main divi¬ 
sions: making crude glycerin from waste lye, and making puri¬ 
fied or distilled glycerin from the crude. 

Coming now to the details of the process, attention is first 
directed to the means for removing alkali, albuminous and rosin- 


400 Glycerin and Its Recovery from Waste Lye. 

ous impurities and remnants of soap. Hagemann for this pur¬ 
pose added first lime and then resin to neutralize the caustic and 
the lye is then concentrated by boiling-; then hydrochloric acid 
was added, and next ferric chloride to precipitate cyanog-en com¬ 
pounds; then followed the forcing of air through the liquid and 
a treatment with clay or alumina, neutralization with soda, and 
then the lye was ready for evaporation. This process, with 
various modifications, was extensively used until it was sup¬ 
planted by treatment with persulphate of iron which results in 
formation of ferric hydrate and iron soaps; the latter, in preci¬ 
pitating, act as clarifying agent and remove considerable al¬ 
buminous and coloring matters. Some free acid contained in 
the sulphate, and some acid added besides, neutralize the lye, 
from which the precipitate mentioned is then removed by a 
filter press. 

The filtrate from the filter press is now to be concentrated 
by evaporation. For this purpose vacuum tanks are used, 
arranged with a view to economize in the use of steam and to 
facilities for keeping the heating apparatus clear of depositing 
salt; as the lye becomes heavier by evaporation of the water, 
more and more salt (sodium chloride and sulphate) is gradually 
separated and removed. The salt is washed to free it from the 
glycerin and then dried to be used over again for graining soap. 
In this manner is obtained at last a crude glycerin which con¬ 
tains about 80 per cent of glycerin, 6 per cent of salt, 5 per cent 
organic impurities, and 10 per cent of water. 

The crude glycerin is then subjected, at home or in a separ¬ 
ate refinery, to the process of distillation. According to the 
figures furnished by a refiner, the best crude obtained from 
waste lye yields about 72 to 74 per cent pure glycerin. (The 
crude glycerin obtained in the stearine industry by saponifica¬ 
tion with steam under pressure yields 82 to 90 per cent). 

Insomuch as the substance of these proceedings is pretty ex¬ 
tensively covered with patents, both as to processes and mach¬ 
inery, it seems advisable to proceed now by referring to the fol¬ 
lowing extracts from the patent records: 

As early as September, 1870, a patent was granted in this 
country (to B. T. Babbitt) for the treatment of sub-lye for the 
recovery of glycerin; there followed patents granted to J. P. 
Battershall (1882) and to C. V. Clolus (1883) and notably those 
granted Oct. 4, 1887, and June 26, 1888, to A. Domeier and O. C. 


Glycerin and Its Recovery from Waste Lye. 401 


Hagemann. The latter patents fairly covered the first processes 
that were really adopted in practice to any extent, i.e., the soapy 
matters are precipitated in the form of insoluble soaps, by means 
of caustic lime, baryte or other metallic oxide, the lye then con¬ 
centrated by boiling’, the still remaining’ fatty and resinous mat¬ 
ters decomposed by means of hydrochloric acid or sulphuric acid 
and removed with kaolin, alum;, or the like; albuminous matters 
still present are removed by boiling’ with soda and the crude 
gdycerin thus obtained distilled and refined in the ordinary way. 
Next followed a patent to E. K. Mitting-, dated July 3, 1888, 
covering- the removal of fatty and resinous impurities by preci¬ 
pitation with chloride of barium or strontium and subsequent 
addition of sulphuric acid; the salt recovered from the spent lye 
is purified by a series of washing’s to remove the gdycerin occluded 
by the salt. An apparatus and process for separating- the salt 
from the boiling- gdycerin liquor was the subject of the next pat¬ 
ent granted to Domeier and Hagemann on May 20, 1890. About 
the same time (Feb. 25, 1890) E. D. Mellen patented the pro¬ 
cess of treating- waste lye (obtained by graining- the soap with 
excess of alkali) by means of carbonic acid, thereby converting 
the alkali into a bicarbonate which is insoluble in glycerin. 
Where caustic lime is used to precipitate insoluble soaps, the 
fatty acids are—according to a* patent granted E. K. Mitting, 
May 20, 1890—recovered by treatment with acid, such as hydro¬ 
chloric, which results in soluble chloride of the metal and free 
fatty acid which is removed; the soluble chloride is treated with 
caustic soda which precipitates the hydroxide of the original 
metal, and the sodium chloride formed is recovered in the subse¬ 
quent evaporation. 

Coming now to more recent times we quote the following 
patents: 

Patent dated June 9, 1891, granted to Albert Domeier and 
O. C. Hagemann: The lye, if it contains alkali worth saving, 
may be first treated according to the previously mentioned pat¬ 
ent of July 26, 1888. Then any free alkali is neutralized by 
some suitable aid; next a metallic oxide or hydroxide—such as 
that of iron or ba^ta—is added to form insoluble metallic soaps; 
acid may now be added from time to time to neutralize the alkali 
set free by the oxide; mechanical stirrers or a current of air are 
used to agitate and heating to 70 or 80° C. may be employed in 
addition. The precipitate, chiefly metallic soaps and albumin- 


402 Glycerin and Its Recovery from Waste Lye. 

ous matter, is removed by decanting’or filtration. Concentration 
by boiling’ to a temperature of 150° C. yields a crude glycerin 
fit for distillation. The process described requires only a single 
tank. 

Patent dated June 9, 1891, granted to O. C. Hagemann: 
First treat the spent lye with lime or other earthy oxide or hy¬ 
drate capable of combining with soapy or rosinous bodies; an in¬ 
soluble precipitate settles to the bottom or is filtered out; evapo¬ 
rate to salt-saturation point; remove the liquid, add hydrochloric 
or other acid to point of neutralization; cool to 30° C. or below; 
add a solution of animal albumen or caseine or other suitable 
proteine body which can be rendered insoluble by adding to its 
dilute alkaline or neutral solution a mineral acid in slight ex¬ 
cess, or a metal salt of an acid reaction, all in the presence of 
much sodium chloride, and provided that the mixture may be 
heated to complete such rendering insoluble of the proteine body. 
A good proportion is one part of blood albumen to about twelve 
hundred parts of the liquor, but more is required with very im¬ 
pure lye; now add to the liquor hydrochloric or another suitable 
acid or a metal salt having an acid reaction, whereby the sapon¬ 
aceous constituents contained in the lye are decomposed and in¬ 
soluble fatty and resinous bodies are formed, and the proteine 
ingredient previously added is being acted upon simultaneously. 
The decomposition of the fatty bodies thus takes place in the 
ubiquitous presence of the proteine ingredient, which is likewise 
rendered insoluble, and is engulfing the fatty bodies as soon as 
separated. The presence of the proteid ingredient predisposes 
the decomposition of fatty bodies to become speedy and very 
complete on account of the insolubility of the proteid precipita¬ 
tion, and also on account of the basic nature of the metallic pro¬ 
teid compound formed. Then gently heat the liquor to cause 
more complete separation and afterward obtain the clear liquor 
by filtration or any well-known means. The metal salts pre¬ 
ferred are aluminum, copper, iron, tin, chlorides, or sulphates, 
and others which may satisfy the requirements, as above ex¬ 
plained. The heating of the treated liquor is more especially 
required where an acid had been employed for the decomposition 
of the saponaceous bodies that were contained in the lye, and 
may be dispensed with in some cases where metal salts had been 
used. To the liquor thus purified now add soda, either caustic 
or carbonate of soda, so as to render the liquor very faintly alka- 


Glycerin and Its Recovery from Waste Lye. 403 


line, and heat to about 80° centigrade, whereby albuminous mat¬ 
ters coag’ulate and fall to the bottom. Finally boil the liquid to 
about 150 centigrade, thereby evaporating- more water, causing- 
the salt which is carried in the liquor to crystallize. This salt 
may be washed and used over ag-ain in the manufacture of soap. 
The first operation—namely, that of adding- lime to the crude 
ly e —may be omitted. Such omission, however, would render 
the treatment more expensive. One also may apply the treat¬ 
ment as described hereinbefore, to follow the preliminary con¬ 
centration to “salting--point,” to soap-lye not preliminarily so 
concentrated, or may g-o further in concentrating- previous to 
such treatment. 

Under date of Sept. 1, 1891, J. Van Ruymbeke patented the 
following-: First treat the lye with an acid (muriatic preferred) 
to neutralize about % of the free alkali of the solution as pre¬ 
viously determined by test. Then add sulphate of iron or of al¬ 
uminum to complete said neutralization; this causes a precipi¬ 
tate of rosinous matter, fatty acids, insoluble soaps of iron or 
aluminum, some hydrate of iron or aluminum and sometimes, 
also, albuminous matter; decant or filter. Next evaporate to re¬ 
move the salts as far as possible and any remaining - impurities 
at the same time; the salt is crystallized out by running-the liquid 
from the filter press to a tank with steam-coils, which are placed 
at some distance above the bottom, in which it is boiled till 
the consistency desired for distillation; the salt settles to the 
space below the coils and may subsequently be reg-ained by a 
centrifug-al filter. The crude gdycerin is in condition for distill¬ 
ation. During- the evaporation the heat of the liquor is increased 
as it becomes more dense; if it is evaporated in the open air it is 
continued till the temperature rises to about 290° F., ora little 
over. But if the evaporation is effected in vacuum, the density 
must be the g-uide instead of the temperature. On cooling-, sul¬ 
phate of soda crystallizes out and is removed previous to distill¬ 
ation. The distillation is effected as follows: 

The solution is placed in a still of any suitable form, which 
is connected with suitable devices for producing-and maintaining- 
a hig-h vacuum within the still. The still is heated with com¬ 
mon or saturated steam, either by means of a coil within the 
still, steam-jacket around the outside thereof, or any other ordi¬ 
nary way. Free steam required for distillation is injected into 
and throug-h the heated liquor within the still, as usual; but this 


404 Glycerin and Its Recovery from Waste Lye. 

steam in this process must be common or saturated steam. The 
steam both for the heating - device and for injection may be taken 
from the same source of supply, if desired. The object is to avoid 
the use of superheated steam, especially the steam which is in¬ 
jected directly into the liquid. Under a high vacuum it is pos¬ 
sible to successfully distil glycerin and other fatty substances 
with common or saturated steam only at a temperature not ma¬ 
terially above 300° Fahrenheit, which is the limit in this pro¬ 
cess. The result of this distillation is asubstantially pure glyce¬ 
rin, the salt, of course being left in the still; but ordinarily it 
will not be sufficiently concentrated for commercial purposes. It is 
only necessary then to concentrate this product of the still by any 
ordinary method of evaporation. Evaporating-pans such as are 
ordinarily used for concentrating liquids are suitable for this 
purpose, and upon bringing the liquid to the proper degree of 
concentration the glycerin is ready for the market. 

In reference to this patent, as compared with previous ones, 
the inventor states: 

“There are the following differences between myprocessde- 
scribed above and prior processes referred to. Instead of entire¬ 
ly neutralizing the free alkali with acids, I only partially neu¬ 
tralize with acid and then complete the neutralization ot the free 
alkali by the addition of metallic salts. The separation of the 
crude glycerin from the precipitate is effected by a filter-press. 
The crude glycerin is separated from the solution of salt in glyc¬ 
erin by distillation with common or saturated steam under a high 
vacuum. These differences result in the following advantages: 
By my method of neutralizing the free alkali of the lye I entire- 
ly obviate the danger of the presence of acid or metallic salts in 
the clarified solution. There will be no acid, because only a por¬ 
tion of the amount required for neutralization being used it will, 
of course, be entirely taken up. There will be no metallic salts, 
because in my method of finishing the neutralization of the free 
alkali by adding metallic salts there results a double decomposi¬ 
tion, metallic insoluble soaps being formed and the mineral acid 
thus freed combining at once with the soda contained in the 
soaps decomposed, while the unneutralized free alkali will unite 
with the acid of the metallic salts to produce mineral salts of soda 
and metallic hydroxides. Now, all these substances are insoluble, 
and hence may be entirely separated from the liquid. Furthermore, 
these substances form a precipitate which is sufficiently hard and 


Glycerin and Its Recovery from Waste Lye. 405 

firm to permit the use of a filter-press in effecting- this separa¬ 
tion. The metallic salts are therefore entirely removed from 
the liquid, because they are entirely taking- up in forming- the 
precipitates mentioned above, which may be entirely separated 
from the liquid. Furthermore, this separation may be effected 
by a filter-press, which effects a great saving of time, a very im¬ 
portant matter in a commercial process, and also effects a saving 
of liquor, because the sediment in separation by the settling pro¬ 
cess, being soft and bulky, retains considerable of the liquid, 
whiuh it is almost impossible to recover by washing. With the 
filter-press in my process, however, a solid cake is left which con¬ 
tains only a small percentage of liquor, and even this may be 
readily removed by washing in the press. In the process of dis¬ 
tillation I avoid all danger of burning the glycerin, for the tem¬ 
perature of saturated steam is very constant and easily main¬ 
tained at about 300° Fahrenheit, which is not sufficient to injure the 
glycerin in any way, and in no case in my process should the 
temperature be carried materially above 300° Fahrenheit, which 
temperature I make the definite limit in the practice of my pro_ 
cess so far as the distillation is concerned. The successful use 
of saturated steam for this distillation is, however, dependent 
entirely upon carrying on the process under vacuum, and a very 
high vacuum at that. I have found that a vacuum of twenty- 
eight inches or more is absolutely necessary to this process, and 
I limit my improvement to this very high vacuum. 

“I am aware that heretofore glycerin has been distilled with 
superheated steam and under vacuum; but I believe I am abso¬ 
lutely the first to successfuly distil glycerin at the low tempera¬ 
ture of 300° Fahrenheit. In fact, in the very latest text-books 
of which I have any knowledge, it is stated that glycerin distils 
under vacuum at 350° Fahrenheit and not lower. 

“Of course in the practice of my process slight immaterial 
variations in the degree of vacuum and in the temperature will 
occur, so that I do not mean to be understood as fixing the limit 
of vacuum at exactly twenty-eight inches or of temperature at 
exactly 300° Fahrenheit; but the racuum cannot be materially 
lower nor the temperature materially higher than the limits 
named above. 

“It will be noted that I here provide a complete process for 
the production of commercial glycerin from spent lye. The ob¬ 
ject of my invention is not to obtain crude glycerin simply, but 


406 Glycerin and Its Recovery from Waste Lye. 

the finished article ready for the trade, and the latter part of my 
process may be applied to the purification of crude glycerin ob¬ 
tained by some method other than that which I have described 
above.” 

On the same date with the last patent a second one was 
granted the same inventor on certain apparatus for carrying* out 
the process. It consists of an open tank for waste lye (tank A) 
placed so that the lye can run from it by gravity into a second 
tank (tank B) placed near it on a lower level; this second tank 
is followed by an ordinary pump (referred to hereafter as C) and 
this in turn pumps the lye to a filter press (referred to below as 
B) which again stands on an elevated platform. From the filter 
press the lye finds its way by gravity to an open, funnel-shaped 
evaporating pan (L) which is provided with an ordinary steam 
coil. Next follows another pump (G) which pumps to another 
tank (H) placed on the same level with the evaporating pan. A 
centrifugal machine (I) is placed conveniently above the last 
mentioned pump and discharges also into the same tank as does 
the pump. Next comes a vacuum still (K) of peculiar construc¬ 
tion; followed by a cooler or condenser (M) discharging into a 
closed receiver (N) provided with a water column and vacuum 
gauge; an ordinary vacuum pump maintains a vacuum in the re¬ 
ceiver and through it in the cooler and in the still itself. Finally, 
the receiver is connected with an ordinary vacuum pan (P) such 
as is used for concentrating liquids. The method of using the 
apparatus for the process last described is given by the inventor 
as follows: 

The tank A is filled or partially filled with the spent soap-lye 
and the quantity contained in the tank determined in any con¬ 
venient way. Three-fourths of the liquid in the tank A is then 
drawn off into the tank B, and to this liquid in tank B there is 
added a sufficient quantity of muriatic acid to exactly neutralize 
it. The remaining fourth of the liquid is then let down from 
the tank A into the tank B and mixed with the neutralized \ye 
in the latter. This operation affords a convenient way of effect¬ 
ing an exact three fourth neutralization of the entire quantity of 
lye. It may be done in some other way; but this mode is very 
convenient and at the same time certain. To this liquid in tank 
B, three-fourths neutralized, there is then added a quantity of 
persulphate of iron, equivalent to one-third of the acid used, and 
well mixed therewith, whereby a complete neutralization of the 


Glycerin and Its Recovery from Waste Lye. 407 

free alkali is obtained and a double decomposition of the soapy 
matter. The liquid is now in proper condition without any 
further treatment for separation in the filter-press D,to which it 
is transferred by the pump C. By the operation of the filter-press 
the clear liquid is received in the pan d\ and thence delivered 
directly into the evaporating-pan E, while the precipitate is left in 
the press in the form of a cake. The liquid received in the evapor¬ 
ating-pan from the filter-press is crude glycerin, salt, and water, 
which is then evaporated in the usual way by means of the steam- 
coil in the said pan. During this process of evaporating the salt 
crystallizes out and drops to the bottom of the tank, which effect 
is greatly facilitated by the arrangement of the coil away from 
the sides of the tank, for the settling of the salt crystals is not 
impaired under this arrangement, as would be the case if 
the coil rested against the inner surface of the pan, in which lat¬ 
ter case the salt would gradually incrust the steam-pipes and so 
impair their action. The narrowing of the tank at the bottom 
also facilitates the separation of the salt crystals from the gly¬ 
cerin as the salt drops into the contracted bottom of the pan, 
leaving above an almost pure solution of glycerin and some salt, 
the evaporating process being continued until the water is most¬ 
ly boiled off and the most of the salt crystallized out. The liquid 
is drawn off from the evaporating-pan and delivered into the tank 
H by the pump G, in which it is allowed to stand and cool, thus 
crystallizing out some more salt and also sulphate of soda, which 
settles at the bottom of the tank. These salts settling at the 
bottom of the evaporating-pan and the tank H are removed to the 
centrifugal machine I, by theoperationof which the crude glycerin 
solution remaining therein is separated from solids and runs off 
through the pipe ** into the tank H. The salts left by this sepa¬ 
ration are suitable for re-use in the manufacture of soap, and thus 
a saving is effected. The clear solution of salt in glycerin stand 
ing in the tank II is now drawn into the still K by the operation 
of the vacuum-pump, which still is especially adapted to the dis¬ 
tillation of the solution in question, and also of all kinds of 
greasy and fatty solutions, oils, &c. In this still the glycerin is 
distilled off and passes into the condenser. As already stated, I 
prefer to obtain the heat necessary for distillation by means of 
steam-coil, for then there is no danger of unduly heating the 
sides of the still, which would lead to burning or incrustation of 
some material upon the inner surface. At the same time I secure 


408 Glycerin and Its Recovery from Waste Lye. 

a regular and equable degree of heat throughout the entire body of 
liquid. At the same time steam is injected directly into the liquid 
through the pipes /, whereby the liquid is agitated and still further 
heated. When steam is thus injected, especially if super-heated I 
have found that small crystals of salt are carried along with the 
vapors of distillation, which of course injure the distillate, which 
will be a clear glycerin, but a little salty. The diaphragm /’ ob¬ 
structs the upward movement of these particles of salt, thereby 
preventing them from passing over with the vapors of distillation. 
The vapors are drawn from the still into the condenser M, where, 
as they pass through the flues, they are condensed by the action 
of the constant current of cold water flowing up through the 
cylinder around the tubes and collect in liquid form at the lower 
end of the condenser, and this liquid is discharged into the re¬ 
ceiver N as a clear aqueous solution of glycerin. In this part of 
the operation I have found that it is desirable to have a vacuum 
of about twent}’-nine inches, under which the glycerin readily 
distills by the application of saturated steam at about sixty 
pounds pressure in the steam-coil of the still, at which low heat 
it is obvious that it is impossible to burn the material. By the op¬ 
eration of the vacuum-pump R the glycerin solution is transferred 
from the receiver N to the vacuum-pan P, where it is concentrat¬ 
ed in the ordinary way to any required density and the concen¬ 
trated glycerin drawn off therefrom through the gate-valve at 
the bottom. The result is a clear pure glycerin. 

The particular construction of the still affords some advan¬ 
tages. Whenever there is occasion to reach the interior of the 
still, it may be accomplished by removing only one-half of the 
top or head, and the same is true of the bottom, so that the still 
may be readily entered from the top or bottom for purposes of 
repair or removal of the salt or any other sediment remaining at 
the bottom of the still, and this can be accomplished without in 
any way disturbing the steam-coil in the interior of the still. 
The perforated diaphragm in this still is a feature of special im¬ 
portance in the distillation of a salty solution of glycerin. 

On Dec. 22, 1891, a patent was granted O. C. Hagemann and 
E. K. Mitting, for a process of using chloride of calcium in place 
of hydrochloric acid, for neutralizing, &c. 

On March 25, 1892, O. C. Hagemann obtained a patent on 
the use of chloride of calcium to neutralize free alkali in the \ye 
and render insoluble contained impurities; its action is to form 


Glycerin and Its Recovery from Waste Lye. 409 

chloride of sodium and carbonate and hydrate of lime with the 
carbonate and hydrate of soda, and to render insoluble organic 
impurities. 

On May 31, 1892, A. Domeier and O. C. Hagemann patented 
a process as follows: The spent lye is mixed with a little caus¬ 
tic lime whereby insoluble lime-soaps are formed and carbonated 
alkali is causticized; after settling the clear liquor is first con¬ 
centrated and then boiled with fat or fatty acids or rosin to take 
up the alkali present; the soap formed thereby is naturally 
grained out by the salts present. The liquor is again drawn off 
(and the lime treatment may be repeated at this stage). Next 
a solution of alum or a chloride (of iron, tin, or zinc) is added 
to precipitate fatty and resinous acids; then follows settling and 
an addition of caustic or carbonated alkali to precipitate any 
excess of alum or of chlorides and of albuminous matters. After 
again settling follows evaporation by boiling to a sp. gr. of 
1.300 at 15 C., and removal of the salt which crystallizes out, 
in accordance with patents granted May 6, 1889. 

June 26, 1894, a patent was granted E. K. Mitting, as fol¬ 
lows: Milk of lime is added to the lye, about one-fifth to one- 
third per cent of the lye, settled and the clear liquor drawn off; 
boil till nearly saturated with salt; treat again with lime, settle, 
decant or filter; boil with fat, fatty acid or rosin to remove all 
free alkali; draw off the lye and again treat with lime to remove 
fatty and rosinous matters still remaining; filter or decant; boil 
down till boiling point is at about 300° F. 

On the same date two patents were obtained by J. Van 
Ruymbeke, one for extracting glycerin from glycerin foots, the 
details of which hardly belong to the present subject, and the 
other patent on a process of recovering glycerin, common salt, 
and Glauber’s salt from spent lye. Drawings of a plant designed 
for the purpose accompany the patent. There is a series of con¬ 
nected settling tanks (or a single tank with compartments) into 
which the lye is run in order to drop heavy impurities and to 
permit lighter ones to be skimmed from the top; next the clari¬ 
fied lie passes to a liming tank for treatment with slacked lime, 
and then it proceeds to a mixing tank; the free caustic and car¬ 
bonated alkali is then determined and ferric sulphate added in 
quantity just sufficient to neutralize this free alkali. Now the 
lye passes through a filter press, being previously heated if neces¬ 
sary to precipitate more fully the ferric hydrate and ferric soap 


410 Glycerin and Its Recovery from Waste Lye. 

formed. The lye now contains still some ferric hydrate, acetate, 
and other salts, hence it goes to another tank where it can be 
brought to a boil to precipitate these; it passes a filter press 
again and then is ready for evaporation. The first salt now pre¬ 
cipitating is mostly sodium sulphate, later the sodium chloride 
precipitates more freely. Evaporation is continued to a point of 
28° B. (30° B. at 15° C.), when the product is about 50 per cent 
glycerin and most of the salt originally in it has separated. For 
evaporation a vacuum apparatus is preferred to an open vessel; 
from this the salt is drawn off at intervals, the adherent lye 
drawn off by suction through a false bottom in the salt tank, and 
the salt washed by steam and condensing water to make it ready 
for use again. The lye of 30 B. as above is further concentrated 
to 34° B., and more salt thereby removed. The result is crude 
glycerin or glycerin saturated with salt and some impurities, 
and is ready for distillation. In place of ferric sulphate, the use 
of some other soluble ferric salt (e. g. chloride) or a salt of al¬ 
uminum (as the sulphate) is provided for in the same patent. 

On July 17, 1894, a patent was granted E. K. Mitting, on a 
process as follows: If the lye contains free alkali worth recover¬ 
ing or is very dark it is treated with lime to clarify it and per¬ 
haps also to causticize carbonated alkali; settle and decant or 
filter; evaporate to about half its bulk; if caustic is present boil 
with fat, fatty acid or rosin. With some lye these preliminaries 
are unnecessary and the proceeding is at once as follows: Add 
bi-sulphate of soda till no more turbidity or precipitate is pro¬ 
duced and the lye is acid in reaction, agitating thoroughly; de¬ 
cant or filter; heat to 80 C. and neutralize with soda or lime; 
filter or decant and then evaporate till it boils at about 300° F. 

On Aug. 13, 1895 a patent was granted H. J. Morrison of 
Clifton, O., on the removal of salt and organic impurities from 
spent lye by first concentrating and then treating with ammonia 
and then with carbonic acid gas, thereby producing bicarbonate 
of ammonia which, with the sodium chloride, forms ammonium 
chloride and sodium bicarbonate. An excess of ammonia is then 
to be boiled off, whereupon a carbonate or oxide of calcium (or 
other metal or alkali) is added to decompose the ammonium 
chloride; calcium chloride forms and is made insoluble by addition 
of sulphuric acid which gives rise to calcium sulphate and hydro¬ 
chloric acid; oxide or carbonate of lead then form an insoluble 
chloride, which is removed with the other precipitates. 


CHAPTER XXI. 


t 

The Simpler Tests and Examinations in the 

Soap Factory. 


The examination of raw materials, such as fats, alkali, es¬ 
sential oils, &c., as well as of the several products of the soap 
factory, involves in many cases comparatively simple manipula¬ 
tion only, which can be of immense benefit however; it is also 
true that in other cases the highest chemical skill is barel} 7 (if at 
all) sufficient to determine the quality and purity of raw ma¬ 
terials purchased, or to follow up the manufacturing- process 
through its various stages. Consequently large factories have 
in their employ thoroughly trained chemists whose constant ex¬ 
aminations frequently prevent loss through purchases of adulter¬ 
ated articles, control the workings of the manufacturing pro¬ 
cess, determine the satisfactory result of the several steps taken 
and the quality of the final products, experiment in new direc¬ 
tions, examine competitive articles, and in general are of great 
assistance in the successful conduct of these large enterprises. 

The smaller factories, in which no chemist is regularly em¬ 
ployed, either, in urgent cases, send their materials for exami¬ 
nation to chemists elsewhere, or rely upon what simple tests they 
can themselves make without such assistance, or—as a last re¬ 
sort—they go without the examinations desired. 

It is not within the province of this book to serve as a guide 
through the very intricate manipulations and calculations which 
enter into certain tests often made in factories which, like the 
soap factory, rest on the foundation of chemistry, as that is a 
large subject by itself, amply taken care of by innumerable books 
for that special purpose, and of interest only to the trained chem- 




412 The Simpler Tests and Examinations in the Soap Factory. 

ist. But in a book intended, like the present one, to give all that 
is of practical value to the practical soap maker , there should evi¬ 
dently be room for an account of those simpler tests which also 
a non-chemist can readily learn to make, and by which the prac¬ 
tical soapmaker can avail himself of at least many of the advan¬ 
tages possessed by larger establishments. 

The aim of this chapter, then, is to collate and describe in 
detail such tests as can be applied to advantage in the soap fac¬ 
tory, without the application of very elaborate instruments, and 
without previous chemical training, as a matter of course, there¬ 
fore, tests selected for the following pages are not always those 
which the professional chemist would prefer when, equipped 
with a complete laboratory, he is looking for the most accurate 
results attainable; but notwithstanding this, the tests given are in 
all cases sufficiently accurate to give highly valuable returns for the 
trouble taken i?i carrying them out; nor is it to be forgotten that 
the average chemist, not being a practical soapmaker, also labors 
under certain disadvantages which often affect the value of his 
services so much that the simpler tests made by the practical man 
may be much more useful after all. 

A small number of utensils or instruments—the costliest of 
which is a good pair of scales—will be useful for so many impor¬ 
tant examinations, that in making the selection of the following 
tests we have given preference—other things being equal—to 
those which permit of the use of the same outfit always, so that 
in following these directions a minimum cost is combined with 
maximum of efficiency and practice. Including the scales, the 
instruments and materials required for making all the following ' 
tests can be procured for probably $35; if it should happen that 
led on by these, the reader should in time take an interest in 
more difficult work and arrange a more pretentious laboratory, 
he will never regret this modest start. 

Preliminary Remarks. 

Have water supply, gas burner or spirit lamp, water bath, 
and if possible a steam supply handy. 

If you can have a drying oven heated by steam and catch the 
waste steam for a supply of distilled water, it will be a great con¬ 
venience. 

For experimental work their is nothing so valuable as a min¬ 
iature soap kettle with steam connections, though work on a 


The Simpler Tests and Examinations in the Soap F actory. 413 

large scale is of course not identical with that in a kettle hold¬ 
ing only say twenty-five pounds. 

A catalogue of some chemists’ supply house will illustrate 
a surprising variety of convenient appliances useful in experimen¬ 
tal work and should therefore be on hand in every soap factory. 

In some of the following tests, requiring weights and mea¬ 
sures, the metric system has been used for description; this is 
done for various reasons, as not only are calculations greatly 
simplefied by it and errors avoided, but apparatus required are 
now made largely on the same plan, current literature on the sub¬ 
ject is now mostly written in the same language, &c. 

ALCOHOL. 

To Test Alcohol as to its Origin 

i. e., whether made from potato, corn, wheat, or other spirit, 
the following simple process is recommended: Put a little of the 
alcohol with an equal quantity of ether in a test tube and shake 
thoroughly for a few moments. Now add an amount of water 
equal to both alcohol and ether. The former combines with the 
water and forms a lower layer, upon which rests the ether, which 
contains all the fusel oil of the original specimen. Withdraw 
with a pipette and evaporate the ether, and the odor of the resi¬ 
due will tell the source of the alcohol. Of course, one must be 
familiar with the odors of the various fusel oils. 

Tests for Water in Alcohol. 

1. On adding a small amount of finely powdered, fused car¬ 
bonate of potassium to aqueous alcohol, and shaking, it becomes 
damp if the alcohol contains not less than about 98 per cent of 
absolute alcohol. In presence of more water it melts. 

2. Alcohol over 98 per cent is miscible in all proportions 
with carbon disulphide. At 98 per cent it is only miscible with 
an equal volume of this liquid, and, if of lower percentage, with a 
proportionately less quantity (Barfoed). 

3. Faintly ignited sulphate of copper, when added to anhy¬ 
drous alcohol, remains perfectly white. In presence of water, 
and shaking, it gradually acquires a blue color, which appears 
the more quickly the more dilute the alcohol is. 

4. On adding a drop of alcohol containing 3 per cent of 
water to 3 or 4 c.c. of benzol, the liquid remains clear. If be¬ 
tween 3 and 7 per cent of water is present, a cloudiness appears; 


414 The Simpler Tests and Examinations in the Soap Factory. 

if over 7 per cent, droplets separate. On dissolving- 1 c.c. of ben¬ 
zol in 2 c.c. of absolute alcohol, it requires the addition of 10 c. 
c. of an alcohol containing- 70.9 per cent by volume before a per¬ 
manent cloudiness appears (Hag-er). 

5. If paraffin oil is dissolved in absolute alcohol or in anhy¬ 
drous chloroform, and this solution mixed with a few drops of 
an aqueous alcohol, and the liquid at once becomes turbid; 
1.500th volume of water may thus be still detected (L. Crismer). 

BORAX. 

The impurities most commonly found with Commercial Borax 
may be divided into two classes, viz.: 

1st. Those impurities which are insoluble in water, such as 
chalk, g-ypsum (plaster of paris), infusorial and other white 
earths. 

2d. Those impurities which, like Borax, are soluble in water. 

Test for Earthy Impurities. 

To test a sample of Borax, for the insoluble impurities, take 
a portion of the pulverized material sufficient to cover a ten-cent 
piece, and place it in a wine-glass of hot water. If the water be¬ 
comes milky, and a white chalky sediment falls to the bottom of 
the glass, the Borax has been adulterated with an insoluble ad¬ 
ulterant. 

If, on the other hand, the whole dissolves, leaving onl} T a 
clear solution, the Borax may yet contain some of the soluble 
adulterants, such as alum, common salt, carbonate of soda, sul¬ 
phate of soda, or some other soluble sulphate. 

Test for Alum. 

To test for the soluble impurities, take sufficient of pow¬ 
dered Borax to cover a twenty-five cent piece, and dissolve in a 
tumbler of hot water. 

Place a portion of this solution in a wine-glass and add a few 
drops of washing ammonia. If a white precipitate forms, alum 
has been added. 

Test for Carbonates and Sulphates. 

To another portion of the liquid, add some muriatic acid. 
An effervescence shows the presence of an adulteration with a 
soluble carbonate. 

After the effervescence has ceased, add a few drops of a 


The Simpler Tests and Examinations in the Soap Factory. 415 

strong- solution of chloride of barium. If the solution becomes 
milky, either immediately or after the lapse of a few minutes, 
the Borax has been adulterated with some soluble sulphate. 

Test for Salt. 

To a third portion of the liquid, add some nitric acid. An 
effervescence shows the presence of a carbonate. When this sub¬ 
sides, add a few drops of nitrate of silver, and heat the solution. 
If salt has been added, it will become milky. 

Test for Soda. 

As a quick test for carbonates, place sufficient of the Borax 
to cover a ten-cent piece, on a saucer, and add a few drops of 
strong vinegar. If the material effervesces, it has been adulter¬ 
ated by the addition of a carbonate (sal soda, etc.) 

ESSENTIAL OILS. 

In the list and description of essential oils (Chapter XVI.) 
are given a number of simple examinations adapted to the oils 
under which the tests are given. To these the reader is referred in 
every case for additional information when any particular oil is 
to be tested, but it remains to speak of certain general features 
of essential oil examinations: 

An examination of an essential oil comprises, in general 
terms: 

A: Examination of physical characters. 

1) Color, odor, consistency. 

2) Specific gravity. 

3) Optical rotation. 

4) Solubility in alcohol, &c. 

B: Estimation of percentage of certain valuable constit¬ 
uents found in certain pure oils, as linalyl acetate in oil 
of bergamot, citral in oil of lemon, &c. 

C: Tests for proving directly the presence of certain sus¬ 
pected adulterants. 

D: Special tests for given cases, as acidity, saponification, 
iodine absorption, and a great many other chemical tests. 

As those who make it a practice to adulterate essential oils 
are in many cases familiar with all the methods of examination, 
they frequently succeed in imitating in their adulterated pro¬ 
ducts also the specific gravity, or the optical rotation, or some 
of the other characteristics of the pure oils, so that it is impos- 


416 The Simpler Tests and Examinations in the Soap Factory. 

sible in many cases to detect adulteration by simple means, or 
even by any means whatever for that matter. But as a rule it is 
not possible to obtain for purposes of adulteration cheap sub¬ 
stances that are not readily detected and at the same time do not 
effect either the specific gravity nor the solubility of the oil in al¬ 
cohol, nor the optical rotation. As to the color and consistency, 
these vary in nature within certain limits and the sophisticators 
easily keep within the natural limits, so these factors are ordin¬ 
arily of little assistance. The odor is still one of the best guides 
to the purity and strength of an oil and must be carefully observ¬ 
ed, but it presupposes the possession of two things by no means 
as common as desirable, namely: thorough acquaintance with.the 
pure oils and a well-trained sense of smell. The test for solubil¬ 
ity in alcohol is in many cases useful, as certain common adult¬ 
erants are less soluble than the pure oils. The estimation of 
the percentage of certain odoriferous constituents in a sample of 
oil is useful in some cases, as the percentage is lowerd by adult¬ 
eration with turpentine, fatty oils, alcohol, &c., &c., but as such 
tests are difficult to make at best, applicable only in few oils, and 
natural oils vary widely in some instances, this method of testing 
is somewhat limited in its usefulness; for instance, much is made 
of the ester contents of lavender oil, but while pure French oil 
contains at least 30%, the highly-valued English oils contain 
less than 10%. 

If it is impossible by the most scientific and skilled methods 
to positively differentiate qualities and detect all adulterations, too 
much must not be expected of course from simple tests that can 
be made by non-experts, but the description of oils in Chapter 
XVI and the following paragraphs contain much that is of prac¬ 
tical assistance and that will go far towards securing good oils. 

In making an examination of any essential oil, the deter¬ 
mination of its specific gravity is properly the first thing to be 
done, as most forms of adulteration affect it; the sp. gr. of each 
oil has been given in the descriptive list and, while slight varia¬ 
tions are not proof positive of adulteration, marked variations up¬ 
ward or downward are extremely suspicious; an increase in specific 
gravity of most oils follows adulteration with fatty oils, essential 
oils of higher sp. gr. &c., while a decrease usually results from alco¬ 
hol, of less sp. gr., &c. The determination can be made by a 
special hydrometer or the Westphal balance or the picnometer. 
Its value varies with the oil to be examined; thus the sp. gr. of 


The Simpler Tests and Examinations in the Soap Factory. 417 

lemon oil is changed but little by adulteration with turpentine 
oil used either alone or together with orange oil; in other cases 
it may be of the greatest service. 

Optical rotation: An optical instrument, the polariscope, is 
used for determination of this factor; it frequently gives very 
useful indications, but owing to its cost few soap manufacturers 
will care to invest in the apparatus. In some cases its tell-tale in¬ 
dications have been safely circumvented by the adulterators, as 
in the example just quoted of lemon oil when mixed with oils of 
turpentine and orange. 

The test of the solubility of an oil in alcohol, where appro¬ 
priate, is easily and cheaply made and for a number of oils is 
a fairly valuable one. By it are discovered adulterants less 
soluble than the pure oils, such as fatty oils,.turpentine oil, and 
cheaper essential oils of less solubility, provided they are present 
in not too small quantity. It is necessary of course, in making 
this test, to strictly adhere to the amounts and strengths of al¬ 
cohol prescribed in the test. 

Adulteration with fatty oils is usually tested for by letting 
a few drops evaporate on clean white paper; pure essential oil 
does not leave a grease spot; if such a spot remains it is not neces¬ 
sarily a sign of adulteration, however, as it may also be the re¬ 
sult of a faulty process in making or in preserving the oils. This 
test may be modified by evaporating a few drops of the oil in a 
watch crystal placed on a water bath and examining the residue, 
if any, for oil, rosin, &c.; on treating the residue with alcohol, it 
will dissolve if it was castor oil or rosin; on then adding water, 
in the case of rosin there will be a flaky precipitate, but if it was 
castor oil it will separate in the form of an oily layer; if the resi¬ 
due was not soluble in the alcohol it is some fatty oil other than 
castor oil. 

Camphor may be detected in oil of peppermint, orange, lav¬ 
ender, cedar wood, caraway, &c., by the following test—(which, 
however, shows the same reaction with oil of sassafras and a 
very similar one with nutmeg and pimento). 

Place a drachm of nitric acid (sp.gr. 1.42) in a test tube, add 
one drop of the suspected oil, and agitate gently. The color of 
the mixture may vary from light yellow to red. If the oil is pure 
the red color will disappear in from twenty minutes to two hours. 
If oil of camphor is present the red color will remain for twenty- 
four hours, and even longer, if not exposed to too strong a light. 


418 The Simpler Tests and Examinations in the Soap Factory. 

This test is reasonably delicate, as less than 5 per cent of oil of 
camphor may be detected by it. 

Alcohol, according- to Hag-er’s suggestion, is most easily de¬ 
tected by the following test which depends upon the insolubility 
of the essential oils in glycerin, and consists in agitating a de¬ 
finite, accurately weighed quantity of the essential oil, and of 
glycerin, together in a test-tube, and subsequently weighing the 
glycerin, any increment being due to the alcohol taken up by it 
from the oil. The details are thus given by Hager: Take a thin- 
walled graduated cylinder, place in it a quantity of glycerin, and 
accurately weigh the whole. Add the suspected oil, using a lit¬ 
tle more in volume than of the glycerin. Shake for five minutes, 
then set aside until the turbid, milky liquid separates into two 
clear layers, the oil being uppermost. If the latter is not quite 
clear, it can easily be made so by warming it up to about 120 F. 
by letting the cylinder stand in hot water for a few moments. 
Remove the bulk of the oil with a pipette, and the remaining 
traces with blotting paper, and again weigh the cylinder and its 
contents. Any increment in weight may be accepted as due 
to alcohol, and, of course, by weighing the oil, we get the per¬ 
centage of adulteration. The only drawbacks to the accuracy of 
this simple process are, first, that certain essential oils contain 
an acid principle, soluble in glycerin; and, secondly, certain of 
the oils are soluble (to a very slight extent only) in alcohol and 
glycerin. The oils containing the acid principle alluded to are 
the oil of cloves, oil of cassia and oil of almonds (essential). 
The evidence of the presence of the acids is a turbidity in the gly¬ 
cerin, greater or less, according to the amount of the acid. The 
second objection is so slight as to be scarcely worth noting, and 
unless very marked, the same may be said of the first. 

Finally, after all, what is wanted in buying an oil is full 
strength and fine aroma, and useful as other tests are, they are asyet 
too incomplete to be relied on alone, especially since an oil ma} 7 be 
pure and answer all scientific tests for purity, and yet have suf¬ 
fered from faulty methods of manufacture, adverse weather con¬ 
ditions, during the growth of the raw materials, bad storage, &c. 
Hence, after all, there is great need of examining the smell of an 
oil to judge of its quality. This manner of testing is carried out 
in practice in several ways, the best of them none too good—the 
others beyond comment. Passing over the simple smelling at 
the open neck of the bottle, at the cork, and at the hands between 


The Simpler Tests and Examinations in the Soap Factory. 419 

which a few drops of the oil were rubbed, the next best and usual 
practice is to dip clean blotting- paper into the oil and smell at 
this paper from time to time, noting- the strength, delicacy, and 
lasting quality of the odor. By using the same size of paper 
slips, dipping them equally deep into different samples of oil, 
till saturated, and exposing them (hanging free) in the same 
place to gradual evaporation, a fair comparison can be made by 
an educated sense of smell. In place of blotting paper the kind 
known as glazed paper can be used to advantage, as it absorbs 
less of the oil and this evaporates more freely and evenly in con¬ 
sequence. Great accuracy, cleanliness, and surroundings free 
from odor, are required for this kind of work, besides practice. 
The paper slips are best marked on the back for identification, 
and the order of smelling them should be occasionally reversed, 
in order to avoid errors of judgment or prejudice from creeping 
in. 


FATS AND OILS. 

The large number of special works on the examination of 
the numerous fats and oils testify to the vastness of this field, 
and to them the reader must have recourse if he desire to enter 
fully into the subject. There are however a few comparatively 
simple tests which can be made by every practical soapmaker and 
which answer most of the ordinary requirements. 

Taking Samples: According to the nature of various fats, 
packages, and methods of filling, it is evident that impurities 
may be either distributed uniformly or they may c'ollect in cer¬ 
tain parts of the packages. To obtain a fair sample it is there¬ 
fore necessary to either take it from several parts of the package 
or to empty the latter, melt and mix, and then take the sample. 
If melting by open steam is used, the water added thereby will 
interfere with the examination for water in the stock 

Tallow: Tallow may contain water, various adulterants 
and animal impurities and dirt, and may be lowered in quality 
by admixture of cheaper fats. Its examination takes cognizance 
of the color, grain, odor, freedom from free fatty acids, water 
&c., and hardness. The melting point is one of the most valu¬ 
able indications of the quality of tallow; instead of on the melt¬ 
ing point of the tallow itself, whose determination by various 
methods does not give uniform results with the same tallow, it 


420 The Simpler Tests and Examinations in the Soap F actory. 

is safer to rely on the melting - point of the fatty acids separated 
from the tallow. 

Melting Point of Tallow: Into a thin-walled glass tube of an 
internal diameter of 3 to 4 mm. draw a little of the melted tallow 
and let congeal thoroughly; then place the tube into a beaker 
with water so that the water is slightly higher in the glass than 
the tallow; apply heat slowly, having a thermometer in the wa¬ 
ter, till the fat is floated to the surface by the water entering 
from below. The temperature of the water at which this occurs 
is the melting point. 

Melted fat does not congeal again until a temperature more 
or less below the melting point is reached; at the moment of 
congealing its temperature rises again at first. The congeal¬ 
ing point of good tallow is not below 88 or 90 F. 

Another method is to apply the fat to the bulb of a thermo¬ 
meter, introducing the latter into water, warming, and noting at 
which temperature the fat becomes detached and rises. 

The Titer Test of Tallow: By this is meant the determina¬ 
tion of the solidifying point of the fatty acids separated from the 
tallow. The methods in vogue comprise saponification of the 
sample with mixed alcohol and soda lye (Dalican’s test) or 
with potash lye (Wolfbauer) or with alcoholic lye (Tate), and 
separation of the fatty acids by sulphuric acid, followed by 
their examination for congealing point. The harder the tallow, 
in other words the higher its melting point and that of its fatty 
acids, the richer is the tallow in stearine. 

This test has several advantages over the simple determina- 
tion of the melting point of the tallow itself; for one thing its 
results do not show the uncertainty and inaccuracy which arise 
from the many different methods followed in finding the melting 
point of tallow. Again a tallow containing more or less free 
fatty acid may have been treated with alkali to neutralize these 
acids, whereby a partial saponification and consequent harden¬ 
ing of the mass results; this deception would not be disclosed by 
simply ascertaining the melting point of the tallow, but a separa¬ 
tion of the fatty acids will lead to a correct estimate of the tal¬ 
low. Age also affects the melting point of tallow differently 
than that of its fatty acids. 

As in all these tests, the one now under consideration 
appears in numerous modifications, but the following of Wolf¬ 
bauer answers all purposes: 


The: SimplerTests and Examinations in the Soap Factory. 421 

120 grammes of the tallow are melted, without heating - much 
more than necessary, in a beaker; mix with 45 cc. of a lye 
made from 1.25 kilo pure caustic potash and 2 liters of water; 
stir till a perfectly homogeneous mass is obtained; cover the 
beaker and set aside in a place kept at 100 C.; stir now and then 
and after two hours see if all is saponified—this is done by dis¬ 
solving a little of it in 50 per cent alcohol, which gives a perfect¬ 
ly clear solution if all is saponified—if not, the mass must remain 
in the hot place a while longer. The soap now obtained is boiled 
with dilute sulphuric acid (165 cc. of 18°) till the separating 
fatty acid floats as a clear layer on top; the mass is covered mean¬ 
while with a glass dish filled with cold water in order to pre¬ 
vent concentration of the acid liquid beneath. The acid solution 
is now drawn off from under the fatty acidsand the latter washed 
by boiling for 15 minutes with a mixture of 5 cc. concentrated 
sulphuric acid and 100 cc. water. After then resting and care¬ 
fully drawing off the acid water, boil again with 100 cc. pure 
water, rest again and remove the water. Now dry the fatty 
acids for 2 hours at 100 C. in an open glass vessel. It now re¬ 
mains to determine their congealing point. For this purpose a 
glass is used, 3}4. cm. in diameter, 15 cm. long, and filled to 
within 1 or l}4 cm. of the brim with the fatty acid. This glass 
is closed by a cork having a large perforation through which a 
thermometer is introduced, (loosely enough to permit stirring 
the contents with the thermometer). The lower % of this glass 
is then inserted in its turn through the perforated cork of a 
large wide mouthed bottle. Now the mass is stirred with the 
thermometer until it just becomes opaque, i. <?., till it is partly 
congealed; the thermometer now sinks no further and stirring must 
be discontinued; the congealing mass at this stage liberates heat 
and the thermometer rises again; the highest point now reach¬ 
ed is taken as the congealing point. 

Errors result from too narrow test glass, faulty thermome¬ 
ter, or careless working. The careless drying of the fatty acids 
especially is a fruitful source of error. As the various tests in 
use stipulate different amounts worked on &c., &c., their results 
never quite agree. 

Water in Fats: To incorporate water in fats, lime, alum, 
potash borax, &c., have been used; 1 per cent of lime or 2-3 per 
cent of alum can be made to cover up over 10 per cent of water 
in this manner. On melting the fat and cooling again, the for- 


422 The Simpler Tests and Examinations in the Soap Factory. 

eign bodies settle and can be ascertained according- to their na¬ 
ture. Where potash was used the fat will not separate clear 
from the water, but will form an emulsion on melting-. 

The ordinary method of testing for water is to dry a sample, 
say 5 grammes, at 100 to 110° C. till the weight is constant and 
calculating the loss as water; a good tallow will require 3-4 hours 
for this test, while grease containing lime will not give up quite 
all its water even in 24 hours’ drying, the lime soap evidently 
retaining the water. 

Free fatty acids in Fat : The fat is washed repeatedly with hot 
water to remove all possible traces of mineral acid. 10 grammes 
of it are then weighed off and shaken with about 25 cc. of warm 
alcohol. It is then titrated with normal soda lye, using phenol- 
phthalein as indicator. (See details of the method under ex¬ 
amination of soda and potash). The number of cc. of lye used 
is multiplied by 0.280 (for cocoanut oil 0.230) to obtain the 
amount of free fatty acid in the sample. 

GLYCERIN. 

Eime in Glycerin. 

For use in transparent soap glycerin is required to be free 
from lime; as some glycerin, however, does contain this impurity 
and thereby impairs the brilliant appearance of the soap, it may 
be tested as follows: Mix 1 part glycerin and 1 part concen¬ 
trated sulphuric acid with 1.100 part 96 per cent alcohol and let 
it rest 3 or 4 days; if lime is present it will manifest itself by a 
white precipitate and turbidity. 

Another test is to simply add ammonium oxalate to the 
glycerin, which gives a white precipitate if lime is present. 

Adulterated Glycerin. 

It is claimed that glycerin is sometimes adulterated with 
syrup or with glucose; if to the suspected sample some sodium 
bi-chromate is added and the whole heated, a coloration indicates 
the presence of sugar. Shaking glycerin with chloroform, if 
glucose be present it will be taken up by the chloroform together 
with other impurities, and the pure glycerin will float on top. 
Glucose is also detected by boiling with caustic soda, which turns 
it brown. 

Pure, waterfree glycerin has a specific gravity of 1.263 to 
1.267 at 15° C. (59 L F.), but as it absorbs moisture with great 


The Simpler Tests and Examinations in the Soap Factory. 423 

readiness it is usually somewhat lighter. A gravity of 1.260 
means about 2 per cent of water in the glycerin, and each varia¬ 
tion of 3 points in the third decimal of the specific gravity is ac¬ 
counted equal to 1 per cent variation in the purity of the glycerin. 

Amount of Glycerin in Waste Eye. 

The amount of glycerin present in a given waste lye is some¬ 
times an important question, but its correct determination re¬ 
quires considerable chemical knowledge and apparatus. A fair 
result can be obtained, however, especially for purposes of com¬ 
parison between several batches of lye, by one of the following 
methods: 

Take 50 cc. of the sample of soap lye, neutralizing exactly 
with dilute sulphuric acid and then add milk of lime; this preci¬ 
pitates the resin and fatty matters which may be present in the 
lye, the mass is filtered and the filtrate evaporated down on the 
water bath. The remaining mass is now treated with a mixture 
of alcohol and ether, the solution separated by filtration from in¬ 
soluble residue and evaporated down in a weighed basin. When 
all the ether and alcohol has evaporated off, the basin and its 
contents are weighed, then the basin is placed over the Bunsen 
burner and all volatile matter burnt off, and the basin and its con¬ 
tents again weighed; the difference between the two weighings 
is taken as the amount of glycerin in the 50 cc. of soap lye. 

A better method, requiring greater manipulation, however, 
is the following: 

A well-mixed sample of the waste lye is filtered, cooled 
thoroughly, filtered again and exactly 1,000 grammes weighed 
off into a porcelain dish fitted on a boiling water bath; enough 
pure hydrochloric acid is now carefully added to cause the lye to 
just turn blue litmus paper red; the acid neutralizes the alkali 
present by changing it into chlorides and also precipitates fatty 
acids and other impurities. The lye is again filtered and 
next boiled down on the water bath to half its volume and then 
10 to 15 grammes of lead acetate is added and stirred well which 
precipitates a bulky mass of lead sulphate, chloride, and organic 
impurities. The liquid is now alkaline again from the basic lead 
acetate, and, in order to separate any excess of lead that may 
have been introduced, concentrated ammonium phosphate solu¬ 
tion is now added drop by drop as long as it causes a white pre¬ 
cipitate; filter through paper and wash the remaining precipi- 


424 The Simpler Tests and Examinations in the Soap F actory. 

tate by throwing- a little hot water on it. The filtrate so re¬ 
ceived is of yellow color and is to be evaporated (on the water 
bath or in vacuum); during this process the very slight amount 
of glycerin evaporated is of no importance to speak of. When 
the liquid is of thin syrupy consistence it is placed—together 
with the salt separated by the evaporation—upon a small suction 
filter from which the fluid runs into a previously weighed flask. 
(When all the liquid has been drawn through the filter, a weigh¬ 
ing of the flask and deducting the weight of the flask gives ap¬ 
proximately the amount of crude glycerin obtained; the latter is 
then examined for its specific gravity and ash remaining after 
ignition as in the previous test, in order to obtain the actual 
glycerin contained in the fluid.) The glycerin retained in the 
salt on the filter paper is best secured by washing it out with a 
little warm alcohol. The crude glycerin still contains some salt; 
hence make slightly acid again with very little hydrochloric acid, 
add an equal amount of absolute alcohol, warm slightly, and 
filter the alcohol solution of crude glycerin through paper upon 
which the salt separated by the alcohol is retained. Next the 
alcohol is boiled off on the water bath and the remainder is 
crude glycerin, the percentage of pure glycerin in the latter 
could then be ascertained also by a process of distillation. 

SOAPS. 

Water in Soap: Take a fair sample, rejecting the hard outer 
portion of hard soaps, (and taking soft soap from the interior of 
the mass). Weigh off accurately a small portion after first cutt¬ 
ing into small shavings, place on a watch crystal and dry, slow¬ 
ly for several hours at first in order to avoid melting the mass 
together, and gradually raising the heat to about 212° F. When 
several successive weighings give the same result, the drying is 
complete and the water driven off is determined by subtracting 
the weight remaining from that of the original undried soap. 
For soft soap or others containing much water it is more practi¬ 
cal to use a beaker, covering the bottom for an inch with clean 
dried sand and weighing it, together with a glass rod. Add a 
small portion of soap and weigh again; now add 3 or 4 times as 
much alcohol and warm on water bath, stirring occasionally, 
till the weight remains constant; the loss is water. 

Amount of fatty acids in Soap: Place a fair, accurately weighed 
sample in a porcelain dish, and pour over it 20 30 times as much 


The Simpler Tests and Examinations in the Soap Factory. 425 

of a mixture over 11 parts water and 1 part sulphuric acid; warm 
slowly till the clear fatty acid rises to the top. To assist in re¬ 
moving- the fatty acids for weighing-, as much dry wax as the soap 
weighed is weighed off and melted together with the fatty acids. 
On cooling the wax together with the fatty acids the whole forms a 
hard solid disk that can be lifted off the liquid beneath. Place 
it on a filter, wash with water till all sulphuric acid is removed 
and dry till weight is constant. Weighing and substracting the 
wax leaves the weight of the hydrates of the fatty acids, so that 
about 2>% per cent must still be deducted from the result to ob¬ 
tain the weight of the fatty acids. Another method, preferably 
where there is danger of vitiating the result by filling matter in¬ 
cluded in the cake of wax and fatty acids, is to dissolve the soap 
in water, separate the fatty acids by sulphuric acid as above and 
then shaking with ether; this is then poured off into a suitable 
weighed vessel, evaporated, the remaining fatty acids dried for' 
2 hours in a drying oven, and weighed; 96.75 per cent of this 
weight is considered actual fatty acid. 

Unsaponified fat in Soap: Dry the soap perfectly; and finely 
powder the soap used to determine the proportion of water as 
above can be used for the purpose; extract with petroleum ether; 
evaporate the latter and the residue will be neutral fat or min¬ 
eral oil (hydrocarbons). By saponification of the residue if this 
is possible its nature can be further determined. 

Filling: Dissolve the soap, previously made into shavings, in 
10 times its weight of alcohol of 90 per cent, assisting the solu¬ 
tion by the water bath; carbonate of soda, silicate, starch, &c., 
remain insoluble; filter and wash the precipitate with alcohol; 
dry it and weigh. To determine the nature of the water-soluble 
portion of the precipitate, extract it with cold water and examine 
portions of the extract; carbonate of soda is determined by titra¬ 
tion; silicate of soda is found by adding an acid to the watery 
solution, when the fatty acids rise to the top while the silicate 
forms a jelly at the bottom; this jelly is collected on a filter, 
washed, dried, and weighed; soap with silicate filling is not quite 
soluble in alcohol as the latter withdraws alkali from the silicate 
leaving the jelly-like mass which is insoluble. On boiling that 
part which is insoluble in alcohol, with water, if starch is present it 
will give a thick solution causing an intensely blue color with 
tinctureof iodine. Talc, silex, &c., are separated easily by their in¬ 
solubility in water; so far as mineral bodies alone are to be deter- 


426 The Simpler Tests and Examinations in the Soap F actory. 


mined, as sand, pumice, silex, &c., a weight sample of the 
soap may be burned in a crucible, digesting the residue with hot 
water, filtering - , drying - the residue, and burning - the latter in a 
weighed crucible; the gain in weight of the latter is mineral 
matter. 

Sugar in soap: Dissolve a sample in water; separate by grain¬ 
ing - with salt; boil the liquid for half an hour with a few drops 
of sulphuric acid (to invert the sug-ar); neutralize with caustic 
soda; take a little of it into a test tube and add an equal amount 
of Fehling’s solution; boil; if sug-ar is present a red precipitate of 
cuprous oxide will form. 

Stock used. The question from what fats or oils a soap is made 
is always very difficult, and frequently impossible, to ascertain 
by chemical means. The practical soap maker can usually 
judg-e better than a chemist can ascertain the facts. A fair idea 
can sometimes be obtained by separating - the fatty acids and then 
examining - these for their melting - point, saponification number, 
iodine number, and certain characteristic reactions. When sever¬ 
al kinds of stock are contained in the soap, the examination is al¬ 
most hopeless. 

Rosin insoap : It is usually easy enough to tell if a soap contains 
rosin or not, but its proportion is more difficult to determine; in 
fact its determination is not possible by any method that could 
be consistently placed among - simple tests. As simple as any is 
Gladding’s method which consists, briefly stated, in separating 
the fatty acids of a sample of soap, dissolving them in 95 per cent 
alcohol, neutralizing with concentrated potash lye using phenol- 
phthalein as indicator, heating on a water bath to perfect saponi¬ 
fication, adding ether, shaking with silver nitrate to precipitate 
the fatty acids, drawing off the clear liquid, adding to the latter 
dilute hydrochloric acid, evaporating the clear liquid to dryness; 
the residue is considered to be rosin. This test in several modi¬ 
fications, and numerous others, are in use, which those who have 
the facilities for carrying them out are quite familiar with. 

Free alkali: The presence of free alkali (caustic or carbon¬ 
ate) is known by a red coloration produced when phenolphth- 
alein is added to an alcoholic solution of the soap. To determine its 
amount, a weighed sample is boiled with distilled water and then 
carefully grained with successive small portions of salt. Any 
free alkali remains in the salt solution which is drawn off, and 
its amount may be determined by titration on the same principle 


The Simpler Tests and Examinations in the Soap Factory. 427 

as already described under the testing - of soda. Another method 
is to test 5 grammes of the soap with 75 cc. of neutral absolute 
alcohol, filtering - , and washing - well with hot alcohol. The filtrate 
is titrated, with phenolphthalein as indicator,to determine the free 
caustic. The insoluble portion on the filter is washed out with 
water and titrated with sulphuric acid, using - methyl orang-e as 
indicator, to determine the carbonate of soda. 

Glycerin in soap : To determine its presence, dissolve a small 
sample of soap in hot water, add dilute sulphuric acid to acid re¬ 
action, melt the fatty acids together with wax as already describ¬ 
ed, and remove same after cooling - . Exactly neutralize the 
remaining - liquid and evaporate on water bath. Sulphate of soda 
and g-lycerin (if present) will remain; treat these with alcohol 
(which does not dissolve sulphate of soda); filter and evaporate 
the alcohol; g-lycerin remains behind, if present. 

SODA AND POTASH. 

The examination of soda comprises testing of commercial 
caustic and carbonate, and sometimes of solutions of the same 
(lye.) As previously noted, when the purity of a caustic is known , 
the lye made from it can be directly examined with a hydrometer 
to tell its strength or quality; but as a solution of salt, or any 
other substance, also shows its degrees on the hydrometer, so a 
mixture of caustic and salt in solution shows higher degrees the 
more of either the one or theother or of both is present in the solu¬ 
tion, and consequently it is absolutely and unequivocally wrong 
to say that the quality of a sample of caustic of unknown com¬ 
position can be examined by dissolving it in water and testing it 
with the lye scale. If this is dwelt on too frequently in this 
book, it is because the error is so far spread that it is almost im¬ 
possible to overcome it. 

Another thing to bear clearly in mind is that the grades of 
caustic soda are based purely on the amount of sodium oxide in 
the same, irrespective of the latter being in the form of caustic 
or of carbonate; hence of two samples both correctly graded at 
say 70 per cent it is quite possible for one to contain 2 per cent 
more carbonate than the other (and of course at the same time 
2 per cent caustic less). In examining caustic for its practical 
value it is therefore necessary to ascertain not only the total al¬ 
kalinity but separately the respective amounts of carbonate and 
of caustic soda. 


428 The Simpler Tests and Examinations in the Soap Factory. 

The purity and strength of an alkali or of an alkaline so¬ 
lution is determined by ascertaining- how much sulphuric acid a 
g-iven amount of it will neutralize; this is the key to the process 
of testing- alkalies (alkalimetry) as well as for making-numerous 
other tests of use in the soap factory. 

For soapmaking- the caustic is used to neutralize/z//y acids; 
for testing- it one might ascertain how much fatty acid a certain 
amount of it can neutralize; but for simplicity and other practical 
reasons sulphuric acid is preferred to fatty acids in making such 
tests. 

As in measurements of any kind whatever a correct measure 
is the first requisite, so the sulphuric acid used in alkalimetry 
must be of known strength; in the following the pure article of 
1.842 sp. gr. at 12° C. is understood throughout. 

49 lbs. of pure sulphuric acid are neutralized by 40 lbs. of 
pure caustic soda. 

49 lbs. of pure sulphuric acid are neutralized by 53 lbs. of 
pure carbonate of soda. 

49 lbs. of pure sulphuric acid are neutralized by 56 lbs. of 
pure caustic potash. 

49 lbs. of pure sulphuric acid are neutralized by 69 lbs. of 
pure carbonate of potash. 

If in the above table we substitute for the “lbs.”: grains, or 
drachms, or ounces, it would of course still be correct. 

Supposing now we had a sample of caustic soda of unknown 
purity, and found by a simple test that 40 grains of it neutral¬ 
ized exactly 49 grains of our pure sulphuric acid, we would then 
know that the caustic was of full strength, i. c ., is chemically 
pure 100 per cent caustic (— 77 l / 2 per cent sodium oxide). But if 
the 40 grains neutralized only y 2 or y as much of the pure sul¬ 
phuric acid, then its alkalinity is only >4 or % of the pure article. 

These simple principles once clearly understood , the following 
detailed description of the test will not only lose all mystery, 
but will give the key to many other tests that can be carried out 
in the soap factory to great advantage, such as alkaline strength 
in waste lyes, free alkali in soaps, &c. Bearing in mind all along 
then the foregoing, and coming to its practical application, we 
find that instead of making these tests by weight, it saves a vast 
amount of work if we dilute our sulphuric acid in a known amount 
of water and then simply measure the amount used for a certain 


The Simpler Tests and Examinations in the Soap Factory. 429 

test; as the volume of dilute acid used is then our indication, this 
method is known as “volumetric analysis.” 

It is evident now that, if we dissolve a certain weight of our 
soda to be tested in water, and run into this the dilute sulphuric 
acid from a graduated vessel, till the soda and acid are just neu¬ 
tralized, the amount of acid used can be read off from the gradu¬ 
ations and a simple calculation will show the rest. This is called 
“titration.” 

There is now only one point more: how shall we know when 
enough acid has been run into our soda solution and the neutral 
point is reached? We may know this by making use of a few 
drops of litmus or a little phenolphthalein or methyl orange, 
(so-called “indicators”) which are introduced into the soda so¬ 
lution at the beginning of our test. Supposing we use litmus, 
the soda solution will color this a marked blue and this color 
remains as we run in gradually the acid; but at last a point 
comes when all the alkali has been neutralized by the acid and 
a single drop of the latter now changes the former blue color to 
red—the solution is no longer alkaline but has become slightly 
acid. In other words, alkaline solutions are blue with litmus 
and acid solutions are red. 

For ease of calculations and because the instruments used 
are ordinarily so graded, the following test is described in the 
metric system which should always be employed in such 
work. 

The Test\ There should be on hand for this class of work a 
pair of scales, a few glass beakers, a glass funnel and filter 
paper, a graduated glass tube holding 50 cc., with stop stock be¬ 
low (a so-called burette) from which the acid can be withdrawn 
drop by drop and the amount used read off, and a holder for the 
burette. There should also be one or several indicators such as 
mentioned before, some reagents called for in certain tests^ 
and the following “normal” or “standard” solutions: 

49 grammes pure sulphuric acid diluted with enough water 
to make one litre. 

40 grammes pure caustic soda diluted with enough water to 
make one litre. 

53 grammes pure carbonate of soda diluted with enough wa¬ 
ter to make one litre. 

56 grammes pure caustic potash diluted with enough water 
to make one litre. 


430 The Simpler Tests and Examinations in the Soap F actory. 

69 grammes pure carbonate of potash diluted with enough 
water to make one litre. 

Comparing- the amounts named for each of these five solutions 
with the table of neutralization a few paragraphs back, it will 
be seen that a given volume of the normal sulphuric acid solution 
exactly neutralizes equal volumes of all the other normal solu¬ 
tions. These normal solutions can be obtained from chemists’ 
supply houses if facilities for making them exactly are not at 
hand. 

Testing sodium carbonate: Weigh off 5 grammes of the alkali, 
place into a flask and make up with water to 250 cc. Fill the 
burette exactly to the 50 cc. mark with the normal sulphuric acid. 
From the flask measure exactly, into a beaker, 25 cc. of the al¬ 
kali solution and add a few drops of methyl-orange solution as 
an indicator (enough to give it a yellow tint); now run in the 
acid solution from the burette very carefully, drop by drop at 
last, stirring carefully, till the alkali solution turns pink which 
shows that all alkali is neutralized and the solution now contains 
a trace of free acid. (Litmus is less suitable for testing carbon¬ 
ate than is methyl-orange). Read off the number of cc. acid 
used, multiply by 0.053, and you have the weight in grammes of 
actual carbonate in the amount of solution tested. A simple self- 
evident calculation finishes the example. 

Potassium Carbonate is tested in the same manner, merely 
substituting in the final calculation the figure 0.069 for the 0.053. 

Caustic soda and potash are tested in the same way, substitut¬ 
ing the figures 0.040 and 0.056 in the final calculation. However, 
as the test does not show at all how much of the alkali present 
is caustic and how much of it is carbonate, this point can be as¬ 
certained as follows: Weigh off 5 grammes as before, dissolve 
in hot water (200 cc. ) and add 50 cc. neutral barium chloride so¬ 
lution, whereby barium carbonate is precipitated; settle, filter, 
wash the precipitate with water to get out all the caustic alkali; 
by now testing with acid and phenolphthalein as before we get 
the alkali present as caustic and the difference between the 
amounts of acid used in the two tests represents the amount of 
carbonate that was present in the sample before it was removed 
by the barium chloride. Another test for the purpose which 
gives probably more accurate results is as follows: Dissolve 2.65 
grammes of the caustic in 50 cc. of water and titrate as before 
with the normal sulphuric acid, using phenolphthalein asindica- 


The Simpler Tests and Examinations in the Soap Factory. 431 

tor and adding- acid drop by drop to the point of decolorizing-, 
stirring- from time to time; note amount of acid used. Now add 
3 cc. normal acid, boil about 5 minutes to expel the carbonic acid 
and titrate back with lye, (The rationale of this is that in the 
first tritration all the caustic alkali is neutralized and half the 
carbonate is chang-ed into bicarbonate). The calculation now is 
as follows: Calling- the number of cc. of acid used for the first 
titration by the letter a, and those for the second b. then the 
sample contained: 

2 (2 a-b) per cent actual caustic soda. 

4 (b-a) per cent carbonate of soda. 

In making- these tests it is by no means immaterial which of 
the “indicators” named is used; for instance, in titrating- caustic 
alkalies cold, with phenolphthalein as indicator, half of the car¬ 
bonate present would appear as caustic, for the reason that bi¬ 
carbonate of soda (or of potash) is found by the carbonic acid 
escaping- from the first half of the decomposed carbonate, and 
this bicarbonate is neutral to phenolphthalein; if now methyl 
orang-e be added and the titration continued till the color chang-es, 
then the bicarbonate will have been turned into sulphate. Making 
a test in just this manner the calculation is as follows: Say 
12.50 cc. of normal acid be required for titration with phenolphtha¬ 
lein, and 0.50 in addition to make the solution neutral to methyl 
orang-e; then 12.50 less 0.50 = 12 cc. is the volume neutralized 
by the hydrate, and 2x0.50 = 1 cc. for the carbonate in the sample. 
To make this test accurately it is best to dilute a gramme of the 
sample to 250 cc. and stirring- continuously while the acid is add¬ 
ed slowly. 

To test potash for soda : A fairly accurate and simple method 
for this purpose is based upon the insolubility of potassium bi¬ 
tartrate in diluted alcohol. The sample is dissolved in a little 
water and neutralized with a concentrated solution of tartaric 
acid (using- phenolphthalein—not litmus—as indicator) ; the same 
amount of tartaric acid solution as was required is then again 
added in order to change the tartrates formed into bitartrates. 
The bitartrate of potash will now mostly precipitate while the 
bitartrate of soda remains in solution; the addition of alcohol 
completes the precipitation entirely. Collect the precipitate on 
a filter and wash with alcohol till the washingsno longer redden 
litmus paper. Now the filtrate is titrated with decinormal (one- 
tenth the strength of normal) caustic potash or caustic soda, 


432 The Simpler Tests and Examinations in the Soap Factory 

each cc. required corresponding- to 0.004 gramme of sodium hy¬ 
drate. The precipitate of pottassium bitartrate may be put in 
water and titrated also with volumetric alkali and phenolphtha- 
lein, each cc. corresponds to 0.056 grammes of potassium hydrate. 

TAR. 

Juniper Tar : Specific gravity varies from 0.978 to 1.102 at 
15°C.; in many respects resembles pine tar; imperfectly soluble in 
95 per cent alcohol (thus differing from pine tar); perfectly sol¬ 
uble in anilin (thus differing from birch tar); a watery extract 
does not give a red color when treated with anilin and hydrochl¬ 
oric acid (distinguishing it from pine tar); watery extract (1.20) 
colored reddish by addition of very dilute (1:1000 solution of 
iron chloride (birch tar extract colored green by same solution). 
Imperfectly soluble in 95 per cent acetic acid. 

Beech Tar\ Sp. gr. 0.925 to 0.945 at 20° C. (68° F.), hence 
floats on water; agitated with 10 volumes of water does not color 
the water, but the latter becomes markedly acid and is colored 
green by the addition of perchloride of iron to the water; if to 5 
ccm. of the water is added 2 drops of anilin and 4 drops of hydro¬ 
chloric acid, a yellow color reaction ensues. If one volume of 
beech tar be agitated with 20 volumes of petroleum ether and 
filtered, a clear brownish liquid is obtained which does not be¬ 
come green when agitated with a diluted solution of copper ace¬ 
tate. Beech tar is but imperfectly soluble in oil of turpentine, 
chloroform, and absolute ether, (vs. pine tar). Perfectly solu¬ 
ble in 95 per cent acetic acid. 

Pine Tar : Sp. gr. 1.02 to 1.05 at 20 C. (68° F.), hence sinks 
in water if entirely free from air bubbles; shaken with 10 vol¬ 
umes of water the latter becomes colored yellow (vs. beech tar) 
and acid; the same water is turned red on the addition of iron 
chloride (instead of green as noted under beech tar); treated 
with anilin and hydrochloric acid, the color passes to red; the 
petroleum ether solution shaken with the dilute copper acetate 
solution (1:1000) is turned green (vs. beech tar); pine tar shaken 
with alcohol does not color the latter, but if it becomes cloudy 
it points to admixture with coal tar, kerosene products, beech 
tar, &c. Perfectly soluble in 95 per cent acetic acid, chloroform 
and absolute ether. 

The above tests are from the writings of Ed. Hirschsohn, 
well known by his examinations of wood tars. 


The Simpler Tests and Examinations in the Soap Factory. 433 

Tar in General. 

To test the disinfecting* power of a given specimen is a com¬ 
plicated and even then unsatisfactory undertaking, it being based 
on a determination of the guayacol percentage and the degree of 
avidity. 

According to W. Adolphi a general idea of the quality of a 
given tar can be obtained by the following simple procedure: 5 
parts by weight of pure caustic are boiled up with 75 parts water; 
to the boiling solution add 25 parts of tar and shake frequently 
while cooling. The dark solution, during the course of a few 
days of rest in a cool place, precipitates more or less of a smeary 
substance which, however, is soluble on adding more water; this 
precipitate is noticed in good as well as in bad tars and must 
therefore be considered as normal. Apart from this precipitate 
a good tar is perfectly saponifiable, but a poor specimen will 
yield on the surface of the above preparation a layer of unsapon- 
ifiable oil, especially if the alkaline solution is further diluted 
with four times its volume of water, /. e. in a solution containing 
1 per cent alkali and 5 per cent of tar. A slightly turbid or 
milky appearance is permissible. 




PART VI. 




























































' 

















. 





Tables, Etc 


Caustic Soda and Caustic Potash Required for Making, or 
Contained in Lyes, of Different Strengths. 


Lye. 

Specific 

Gravity. 

100 lbs. lye contain of 

Caustic 

Soda. 

Caustic 

Potash. 

1° B. 

1.0070 

0.61 lbs. 

0.90 lbs. 

5° “ 

1.0360 

3.35 “ 

4.50 “ 

8° “ 

1.0588 

5.29 “ 

7.40 “ 

10° “ 

1.0746 

6.55 “ 

9.20 “ 

12° “ 

1.0909 

8.00 “ 

10.90 “ 

15° “ 

1.1163 

10.05 “ 

13.80 “ 

18° “ 

1.1423 

12.64 “ 

16.50 “ 

20° “ 

1.1613 

14.37 “ 

18.60 “ 

25° “ 

1.2101 

18.58 “ 

23.30 “ 

30° “ 

1.2632 

23.67 “ 

28.00 “ 

35° “ 

1.3211 

28.83 “ 

32.70 “ 

38° “ 

1.3585 

32.47 “ 

35.90 “ 

40° “ 

1.3846 

34.96 “ 

37.80 “ 

45° “ 

1.4545 

41.40 “ 

43.40 “ 

50° “ 

1.5319 

49.00 “ 

49.40 “ 


If these lyes are made of 
chemically pure caustic 
alkali the actual caustic 
content is expressed by 
the figures. 

If the lyes are made of 
lower grades the actual 
caustic strength is pro¬ 
portionately decreased, 
as the grade of caustic 
alkali is lower. 

The degrees on the hydro¬ 
meter refer to a temper¬ 
ature of 60° F. in cool¬ 
ing from the boiling 
point to 60 F., lyes in¬ 
crease from 4^2 to 5 B. 
in density. 


Aukali Required for Saponification. 


There are required 
for the complete sa¬ 
ponification of 

Caustic Soda. 

Caustic 
Potash. 

77*4 p.c. 
Cliern. 
Pure. 

77 p.c. 

76 p.c. 

74 p.c. 

70 p.c. 

60 p.c. 

Chem. 

Pure. 

100 Ibs.cocoanut oil* 
100 “ tallow*. 

17 42 lbs. 
13.95 “ 

17.53 lbs. 
14.04 “ 

17 76 lbs. 
14.22 “ 

18.24 lbs. 
14.61 “ 

19.29 lbs. 
15.44 “ 

22.5 lbs. 
18.2 “ 

24.4 lbs. 
19.54 “ 


*These calculations are theoretical, and made on the basis of very pure fat. Fats 
and oils that contain impurities will absorb correspondingly less al Uali. The figures for 
grease, cotton seed oil, and other fats (except cocoannt oil) are nearly the same as for 
tallow. In practice for boiling soaps more alkali is required than stated above on ac¬ 
count of at least some unavoidable waste. For cold-made or half-boiled soap the above 
proportions are substantially correct, as no lye is run away in their manufacture. Cir¬ 
cumstances, of course, figure largely in actual practice. 












































438 


Tables, Etc. 


Temperature of Wet Steam at Various Degrees of Pressure. 


As the pressure in the steam boiler rises the temperature of 
the steam is increased, so that for operations intended to evapo¬ 
rate considerable water from the soap an increased steam pressure 
gives the fastest result. 

Tp:mperature. Pressure. 


Degrees F. 

32. 

212 . 

248. 

275.. 

293. 

311. 

320. 

428. 


lb. per sq. inch. 

.08 

. 14.70 

. 28.83 

. 45.49 

. 60.40 

. 79.03 

. 89.86 

.336.30 


Expansion of Oils by Heat. 

When the quantity of oils and fats run into the kettle is re¬ 
gulated by measurement, the temperature of the stock is a not 
unimportant item, as in common with other liquids, oils expand by 
heat so much that, for instance, 1,000 gallons of oil at 32° F. will 
make 1,018 to 1,025 gallons at 75 c F., according to the kind of oil. 

This expansion is therefore more considerable in fats and 
oils than in ordinary fluids. 

Metric Weights and Measures. 

1 Hectoliter (100 litres) = 26,4175 U. S. gallons. 

1 Liter = 2,1134 American pints (=61.024 

cubic inches.) 

1 Kilogram (1000 grams) = 2,205 lbs. avoirdupois. 

1 Oram = 15,4384 grains. 

1 Kilometer (1000 meters) = 0,62138 mile. 

1 Meter = 39,3795 American inches. 

1 cubic centimeter (c. c.) = 16.23 minims. 

The prefixes used in the metric system have the following 
meaning: 

Kilo—meaning one thousand. 

Hecto—meaning one hundred. 

Deka—meaning ten. 

Deci—meaning one-tenth. 

Centi—meaning one-hundredth. 

Milli—meaning one-thousandth. 










Tables, Etc. 


439 


Avoirdupois Weight. 

1 lb. = 16 ounces == 256 drachms. 

1 ounce = 16 drachms. 

The pound avoirdupois equals 7000 grains in weight. There 
is no grain in the avoirdupois weight—as found in some tables— 
but only one uniform grain (that of the troy weight) exists. 

Troy (Apothecaries’) Weight. (U. S.) 

1 pound-12 ounces = 96 drachms = 288 scruples = 5760 grains. 

1 ounce = 8 drachms = 24 scruples = 480 grains. 

1 drachm = 3 scruples — 60 grains. 

1 scruple — 20 grains. 

Wine (Apothecaries’) Measure. (U. S.) 

The U. S. gallon contains 231 cubic inches and equals 
0.83292 British gallon. 

1 gallon = 8 pints = 128 fl. ozs. = 1024 fl. drachms= 61440 minims. 

1 pint = 16 fl. ozs. = 128 fl. drachms = 7689 minims. 

1 fl. oz. = 8 fl. drachms = 480 minims. 

1 fl. drachm — 60 minims. 

Imperial Measure. 

The Imperial (British) gallon contains 277.27384 cubic inches 
and equals 1 gallon 1 pint 9 fl. oz. 5 fl. drs. and 8 minims of the 
United States gallons. 

1 gallon = 8 pints=160 fl. ozs.=1280 fl. drachms=76800 minims. 

1 pint = 20 fl. oz. = 160 fl. drachms= 9600 minims. 

1 fl. oz. — 8 fl. drachms= 480 minims. 

1 fl. drachm = 60 minims. 

THE THERMOMETER. 

« 

The thermometric scales chiefly in use are those of Fahren¬ 
heit, Celsius (better known as the “Centigrade” scale), and 
Reaumur, in which the interval between the normal freezing and 
boiling points of water is respectively divided into 180, 100, and 
80 degrees. The Reaumur scale is but little used except in some 
parts of Germany. The several degrees compare with each 
other in this manner: 


440 


Tables, Etc. 


1° F. = *55° C. or *44° R. 

1° C. = 1*80° F. or *80° R. 

1° R. = 2-25° F. or 1*25° C. 

The zero of both the Centigrade and Reaumur scales is placed 
at the freezing point of water, while with Fahrenheit’s thermom¬ 
eter 0° comes 32 degrees below, hence in converting any temper¬ 
ature on one scale to its equivalent on another, one of the 
following methods must be adopted: 

A given temperature in Centigrade deg. divide by 5 multiply 
by 9 add 32. The result is temperature in Fahrenheit deg. 

A given temperature in Centigrade deg. divide by 5 multiply 
by 4. The result is temp, in Reaumur deg. 

A given temperature in Fahrenheit deg. — 32 divide by 9 
multiply by 5. The result is temp, in Centigrade deg. 

A given temperature in Fahrenheit deg. — 32 divide by 9 
multiply by 4. The result is temp, in Reaumur deg. 

A given temperature in Reaumur deg. divide by 4 multiply 
by 9 add 32 equals temp, in Fahrenheit deg. 

A given temperature in Reaumur deg. divide by 4 multiply 
by 5. The result is temp, in Centigrade deg. 

It is, as a rule, only Centigrade and Fahrenheit degrees with 
which temperature are marked in this country. 


TABLE SHOWING CENTIGRADE DEGREES AND THEIR 
EQUIVALENT ON FAHRENHEIT’S SCALE. 

For the ready conversion of Centigrade into Fahrenheit de¬ 
grees, the following table will be useful. 


Fok Temperatures Below the Freezing Point of Water. 


c. 

F. 

C. 

F. 

C. 

F. 

C. 

F. 

C. 

F. 

c. 

F. 









— -4- 


+ 

o 

0 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

40 

40*0 

33 

27*4 

26 

14*8 

19 

2*2 

15 5-0 

< 

19*4 

39 

38*2 

32 

25*6 

25 

13*0 

18 

0*4 

14 6*8 

6 

21*2 

38 

36*4 

31 

23*8 

24 

11*2 

17*778 0*0 

13 8*6 

5 

23*0 

37 

34*6 

30 

22*0 

23 

9*4 

— 

+ 

12 10*4 

4 

24-8 

36 

32-8 

29 

20-2 

22 

7*6 


o 

11 12*2 

3 

26*6 

35 

31*0 

28 

18*4 

21 

5*8 

17 

1*4 

10 14*0 

2 

28*4 

34 

29*2 

27 

16*6 

20 

4*0 

16 

3*2 

9 15*8 

8 17*6 

1 

0 

30*2 

32*0 




















Tables, Etc. 


441 


For Temperatures Above the Freezing Point of Water. 


c. 

F. 

c. 

F. 

C. F. 

C. F. 

C. F. 

c. 

F. 

+ 

+ 

+ 

+ 

+ + 

+ + 

+ + 

+ 

+ 

o 

o 

o 

o 

o o 

o o 

o o 

o 

o 

1 

33*8 

68 

154.4 

135 275-0 

202 395*6 

269 516-2 

336 

636*8 

2 

35*6 

69 

156*2 

136 276-8 

203 397*4 

270 518*0 

337 

638*6 

3 

37*4 

70 

158*0 

137 278*6 

204 399*2 

271 519*8 

338 

640*4 

4 

39-2 

71 

159*8 

138 280*4 

205 401*0 

272 521*6 

339 

642*2 

5 

41-0 

72 

161*6 

139 282*2 

206 402*8 

273 523*4 

340 

644*0 

6 

42*8 

73 

163*4 

140 284*0 

207 404*6 

274 525-2 

341 

645*8 

7 

44*6 

74 

165*2 

141 285*8 

208 406*4 

275 527 -0 

342 

647*6 

8 

46’4 

75 

167*0 

142 287*6 

209 408*2 

276 528*8 

343 

649*4 

9 

48*2 

76 

168*8 

143 289*4 

210 410*0 

277 530-6 

344 

651-2 

10 

50*0 

77 

1706 

144 291*2 

211 411*8 

278 532*4 

345 

653*0 

11 

5P8 

78 

172*4 

145 293-0 

212 413*6 

279 534*2 

346 

654*8 

12 

53-6 

79 

174-2 

146 294*8 

213 415*4 

280 536*0 

347 

656*6 

13 

55*4 

80 

176-0 

147 296*6 

214 417*2 

281 537-8 

'348 

658*4 

14 

57-2 

81 

177-8 

148 298*4 

215 419*0 

282 539 6 

349 

660-2 

15 

59*0 

82 

179-6 

149 300*2 

216 420-8 

283 541*4 

350 

662*0 

16 

60-8 

83 

181-4 

150 302*0 

217 422-6 

284 543-2 

351 

663*8 

17 

62-6 

84 

183*2 

151 303-8 

218 424*4 

285 545-0 

352 

665*6 

18 

64*4 

85 

185*0 

152 305-6 

219 426*2 

286 546*8 

353 

667*4 

19 

66*2 

86 

186-8 

153 307-4 

220 428 0 

287 548*6 

354 

669-2 

20 

68*0 

87 

188-6 

154 309*2 

. 221 429*8 

288 550*4 

355 

671-0 

21 

69-8 

88 

190*4 

155 311*0 

222 431-6 

289 552.2 

356 

672*8 

22 

7P6 

89 

192-2 

156 312-8 

223 433*4 

290 554*0 

357 

674-6 

23 

73-4 

90 

194*0 

157 314-6 

224 435*2 

291 555-8 

358 

676*4 

24 

75*2 

91 

195-8 

| 158 316*4 

225 437*0 

292 557-6 

359 

678*2 

25 

77*0 

92 

197-6 

1 159 318*2 

226 438*8 

293 559*4 

360 

680*0 

26 

78*8 

93 

199-4 

160 320*0 

227 440*6 

294 561-2 

( 361 

681*8 

27 

80-6 

94 

201*2 

161 321-8 

228 442*4 

295 563*0 

362 

683*6 

28 

82-4 

95 

203*0 

162 323*6 

229 444*2 

296 564*8 

363 

685*4 

29 

84*2 

96 

204*8 

163 325*4 

230 446*0 

297 566*6 

364 

687*2 

30 

86*0 

97 

206*6 

164 327 -2 

231 447*8 

298 568*4 

365 

689*0 

31 

87-8 

98 

208*4 

165 329-0 

232 449*6 

299 570-2 

366 

690*8 

32 

89-6 

99 

210*2 

166 330-8 

233 451-4 

300 572*0 

367 

692-6 

33 

91*4 

100 

212-0 

167 332 6 

234 453-2 

301 573*8 

368 

694*4 

34 

93*2 

101 

213*8 

168 334*4 

235 455-0 

302 575*6 

369 

696-2 

35 

95*0 

102 

215-6 

169 336*2 

236 456-8 

303 577-4 

370 

698*0 

36 

96-8 

103 

217*4 

170 338*0 

237 458-6 

304 579*2 

371 

699-8 

37 

98*6 

104 

219*2 

171 339-8 

238 460*4 

305 581*0 

372 

701*6 

38 

100*4 

105 

221*0 

172 341-6 

239 462*2 

306 582-8 

373 

703-4 

39 

102*2 

106 

222-8 

173 343*4 

240 464*0 

307 584*6 

374 

705-2 

40 

104*0 

107 

224*6 

174 345-2 

241 465*8 

308 586*4 

375 

707-0 

41 

105-8 

108 

226-4 

175 347-0 

242 467*6 

309 588-2 

1 

376 

708*8 







































442 


Tables, Etc. 


C. F. 


42 

107-6 

43 

109-4 

44 

111-2 

45 

113*0 

46 

114-8 

47 

116-6 

48 

118-4 

49 

120-2 

50 

122*0 

51 

123*8 

52 

125*6 

53 

127-4 

54 

129-2 

55 

131-0 

56 

00 

CO 

H 

57 

134-6 

58 

136-4 

59 

138-2 

60 

140-0 

61 

141*8 

62 

143*6 

63 

145-4 

64 

147-2 

65 

148-0 

66 

150-8 

67 

152-6 


C. F. 


109 

228-2 

110 

230-0 

111 

231-8 

112 

233*6 

113 

235-4 

114 

237-2 

115 

239-0 

116 

240-8 

117 

242-6 

118 

244-4 

119 

246*2 

120 

248-0 

121 

249-8 

122 

251-6 

123 

253*4 

124 

255*2 

125 

257*0 

126 

258-8 

127 

260-6 

128 

262 -4 

129 

264*2 

130 

266-0 

131 

267-8 

132 

269-6 

133 

271-4 

134 

273-2 


C. F. 


176 348*8 

177 350*6 

178 352-4 

179 354-2 

180 356-0 

181 357-8 

182 359-6 

183 361-4 

184 363-2 

185 365-0 

186 366*8 

187 368-6 

188 370-4 

189 372-2 

190 374-0 

191 375-8 

192 377-6 

193 379-4 

194 381-2 

195 383-0 

196 384-8 

197 386*6 

198 388-4 

199 390-2 

200 392-0 

201 393-8 


C- F. 


243 469*4 

244 471-2 

245 473-0 

246 474-8 

247 476-6 

248 478-4 

249 480-2 

250 482-0 

251 483 8 

252 485*6 

253 487-4 

254 489-2 

255 491-0 

256 492-8 

257 494-6 

258 496*4 

259 498*2 

260 500-0 

261 501-8 
2b2 503-6 

263 505-4 

264 507-2 

265 509-0 

266 510*8 

267 512-6 

268 514-4 


C. F. 


310 590-0 

311 591 *8 

312 593*6 

313 595*4 

314 597-2 

315 599*0 

316 600*8 

317 602*6 

318 604*4 

319 606-2 

320 608*0 

321 609*8 

322 611-6 

323 613-4 

324 615-2 

325 617-0 

326 618-8 

327 620-6 

328 622-4 

329 624-2 

330 626-0 

331 627*8 

332 629-6 

333 631-4 

334 633-2 

335 635*0 


C. F. 


377 710-6 

378 712-4- 

379 714-2 

380 716-0 

381 717-8 

382 719-6 

383 721-4 

384 723-2 

385 725-0 

386 726-8 

387 728*6 

388 730*4 

389 732*2 

390 734-0 

391 735*8 

392 737*6 

393 739-4 

394 741-2 

395 743-0 

396 744-8 

397 746-6 

398 748-4 

399 750-2 

400 752-0 
450 842-0 
500 932-0 





















Appendix. 


Introduction. 

Not only is the formation of soap from fats and alkali a true 
chemical process, and therefore best explained by reference to 
the fundamental principles of chemistry, but the numerous raw 
materials employed, and the various stages of manufacture also 
offer many opportunities for profitable as well as interesting 
chemical observation. In late years soap makers have more and 
more taken up the study of this science, and with so good results 
that whereas the manufacture of soap was once enshrouded in 
mysteries, the soap maker of to-day at least understands the reas¬ 
ons underlying the facts that come daily under his practical ob¬ 
servation. Formerly, attempts were numerous to improve the 
art of soap making by new processes, the impossibility of which 
would have been plain at once to every chemist; but in their 
stead chemistry has made possible improvements which, without 
this science, would undoubtedly never have been thought of. 
The manufacture of soda ash and caustic soda from salt, and 
the recovery of glycerin from spent lyes, are notable examples of 
this fact. 

It is undoubtedly possible to be a practical soap maker with¬ 
out understanding even the first principles of chemistry, but it 
is also safe to predict that every practical soap maker would be 
less dependent on chance and would acquire a much clearer knowl¬ 
edge of his calling by familiarizing himself with chemistry, at 
least sufficiently to thoroughly understand those principles on 
which soap making is based. 

The foregoing pages have been written with a view to cover 
the requirements of practical soap makers, whether they have 
any knowledge of chemistry or not, and it is not within the pro- 



444 


Appendix. 


vince of this book to teach the rudiments of that science. But 
many of the facts pointed out in these pages will acquire greater 
significance and be more distinctly understood by the reader 
when viewed in the light of the teachings of chemistry. 

Not only is this science of great use in aiding the practical 
manufacturer to properly understand his work, but it also gives 
him the means of conducting practical operations, and, in fact, 
his entire business to better advantage: It enables him to de¬ 
tect adulterations in the raw materials, to discover and remedy 
the causes of occasional irregularities in his work, to avoid waste, 
to work out improvements, and last, but not least, it places him 
in a position to judge intelligently of the practical value of new 
materials and methods. 

4* 'f* 't* 'f' ^ 

Note 1: 

Alkalies are the oxides of the so-called “alkali metals,” 
these being the metals that oxidize readily in the air, are lighter 
than water, and decompose the latter at ordinary temperatures 
with the liberation of hydrogen and the simultaneous formation 
of their hydroxides. [In the case of ammonia (NH 3 ) it is con¬ 
sidered that, when dissolved in water, it forms the hydroxide N 
H 4 HO in which the radical “ammonium” (NH,) is of metallic 
character in its chemical behavior.] These alkalies are the 
strongest bases known and unite with water to form “hydrates,” 
i. e. the caustic alkalies. 

Alkaline Earths may be defined as oxides of certain metals 
(called the alkaline earth metals), namely of calcium, strontium, 
and barium; magnesium may also be included in the group, al¬ 
though it has very little of an alkaline character. They derive 
their name from the fact that they resemble on one hand the 
oxides of the alkali metals, and on the other hand arrange them¬ 
selves with the true earths. 

Note 2: 

Almost all fats and oils are “glycerides,” or ethers of glyce- 
rin. Glycerin is an alcohol, for the alcohols are those compounds 
that are formed when the radical HO is substituted for one or 
more atoms H in a compound of hydrogen and carbon; thus the 
hydrocarbon ethane, C 2 H 6 , forms the ordinary alcohol C 2 H 5 HO 
in the manner stated. Similarly the substitution of three atoms 


Appendix. 


445 


°f H by as many groups HO in the hydrocarbon C 3 H„ forms the 
alcohol glycerin, C 3 H 3 (HO) 3 . The alcohols therefore are the hy¬ 
drates of the alcoholic radicals. Some fish oils contain ether-like 
compounds of a different alcohol, Cetyl-alcohol; wool fat con¬ 
tains the ether of cholesterin. Ethers may be simple or com¬ 
pound, the simple ethers being- the oxides of the alcoholic radi¬ 
cals, formed by the action of acids on the alcohols, thus: 


C H 5 HO 


c 2 h 5 ) 


5 1 o 

c 2 h 5 i u 


forms 

Ethyl hydrate = alcohol. Ethyl oxide = ether. 

The compound ethers are formed by the double decomposi¬ 
tion of an acid and an alcohol, as in the following example: 

O 

Ethyl Nitric Water Nitric 
hydrate acid ether 

From the action of fatty acids on glycerin in this manner 
the compound ethers, which constitute the fats and oils, are de¬ 
rived, thus: 


C 2 H 5 \ n NO, ) n _H ) n N0 2 \ 
H f ° + j C 2 H 5 j 


3C 18 H 35 0 ) I C 3 H 5 ) ^_3H j q T (Ci 8 H 35 0) 3 ) ^ 

H|°+ H 3 i° 3 -Hf U C 3 H 5 i ° 3 
Stearic acid Glycerin Water Stearin 

This reaction may be actually obtained by heating for 3b 
hours, in a closed tube, certain parts of glycerin and stearic acid 


Note 3: 

The organic acids may be considered as derived from the 
alcohols (as indeed occurs in making vinegar [—acetic acid], 
which belongs to the fatty acids—from alcohol), by replacing O 
for H 2 : 

C 2 H 6 0 : C,>HA 

« Alcohol Acetic acid 


Note 4: 

The formation of soap and separation of glycerin on boiling 
a fat with caustic lye is represented by the following equation: 

(C 18 H 35 0) 3 ) q _ 3C 18 H 35 0 I q , C 3 H 5 ( q 

C 3 H 5 j O^+^NaOH— Na f U + H 3 J 

Stearin Caustic soda Sodium stearate Glycerin 

(Soap) 


446 


Appendix. 


Note 5: 

The decomposition, by water, of neutral soap into a mix¬ 
ture of alkaline and of acid soap, may be illustrated by the fol¬ 
lowing - : 

3(C 18 H 35 0 2 Na)+H0=C 18 H350. 2 Na0HNa+C 18 H3 5 0,NaC 18 H360 2 


Note 6: 

The principal fatty acids are the following - : 

Found principally in: 

C 4 H s 0 2 .Butter. 

Ci 2 H 24 0 2 .Cocoanut oil. 

c 1( h 28 o 2 . 

C 16 H 32 0 2 .Lard, tallow, palm oil. 

C 18 H i6 0 2 .Lard, tallow. 

c 18 h 34 o. “ 

C ]6 H 26 0 2 .Linseed oil. 


Butyric acid 
Laurie acid 
Myristic acid 
Palmitic acid 
Stearic acid 
Oleic acid 
Linoleic acid 


Ricinoleic acid C 1S H 34 C >3 .Castor oil. 


Note 7: 

The influences at work in turning - fats rancid have been 
made a study by many eminent investigators, but no final con¬ 
clusion has been reached. It has been held—by Liebig and 
others—that the foreign admixtures, such as albumen, mucous, 
etc., in a fat acted as a kind of ferment; others considered that 
the impurities merely attract oxygen and yield it to the fats; ac¬ 
cording to another view (by Berthelot) moisture is the first cause 
of rancidity; and Virchow and others ascribe it to the action of 
certain micro-organisms. Ed. Ritsert, by a series of experiments, 
found that when the air is excluded , sterilized lard will not turn 
rancid, even if it contains moisture, and is subjected to sunlight. 
Nor did it become rancid when exposed to the air and the light 
excluded . When exposed to hath sunlight and air the lard turned 
distinctly rancid within a week, but no bacteria could be found 
in the fat. It may occur that micro-organisms are found in ran¬ 
cid fat, as in so many other substances, but when such organ¬ 
isms were introduced into sterilized lard and the latter exposed 
to the sun, it developed more free fatty acids and yet the micro¬ 
organisms died. It seems to be established by these trials that 
sunlight and air together are able to cause rancidity of fats, and 
that micro-organisms are not concerned in the change. Ferments 
also do not seem to take part in it, for sterilized fat that had 










Appendix. 


447 


been heated to a temperature at which all known ferments are 
killed, turned rancid after exposure to light and sterilized air or 
oxygen, F at freed from moisture turned even more rancid than 
fat charged with it, so that moisture does not appear to be so 
important a factor in the process as was supposed. 

Note 8: 

Sodium oxide and water combine according to the following 
formula to form caustic soda: 

Na 2 0+H 2 0=2Na0H, 

and according to the atomic weights (Na=23, 0=16, H=l) it 
follows that 62 parts NaO and 18 parts water, form 80 parts sodi¬ 
um hydrate. 

Note 9: 

The decomposition of soap by salts contained in hard water 
is shown by the following formula: 

2C 18 H :!5 Na0. 2 +CaH 2 (C0 3 ) 2 =Ca(C 18 H 35 0 2 ) l +2NaHC0; { , 
Sodium Calcium Calcium Sodium 

stearate bicarbonate stearate bicarbonate 

Note 10: 

Caustic soda or lime are frequently employed to soften hard 
water when the hardness is caused by carbonates; the reaction 
which reduces the hardness is as follows: 

Ca H 2 (CO.t) 2 +Ca (OH ) 2 =2CaC0 3 +2 FLO, 

Calcium Calcium Calcium Water 
bicarbonate hydrate carbonate 
The bicarbonate of lime causing the hardness is by this re¬ 
action changed into the insoluble carbonate, which precipitates. 

Note 11: 

The reaction taking place in separating a potash soap by 
means of salt is a double decomposition, the hydrochloric acid of 
the salt combining with the potash, and the fatty acids combin¬ 
ing with the soda. When carbonate of potash is added to a soda 
soap, some potash soap and carbonate of soda is formed. Both 
changes are due to the fact that when both soda and potash are 
present, combined with two acids, the potash has a tendency to 
combine with the stronger acid. Hydrochloric acid is stronger 
than fatty acids, and these are stronger than carbonic acid. How¬ 
ever, when only fatty acids are present, and the soda and pot- 


448 


Appendix. 


ash are both caustic, they seem to combine with equal preference 
for the several fatty acids. 

Note 12: 

The formula for both, silvic and pinic acid is C 2() H 30 O,, they 
being- isomeric. 

Note 13: 

Soda ash and potash are made caustic by the action of quick¬ 
lime by the withdrawal of carbonic acid, as follows: 

Na 2 C0 3 + Ca (H0) 2 ==CaC0 3 +2Na HO: 

Carb. soda Calcium Calcium Caustic soda 
Hydrate Carbonate 


Note 14: 

The decomposition of fat by means of heat and water (steam) 
into fatty acids and glycerin (compare also Note 2) is effected 
according to the following formula: 

C 3 H 5 f Ua Hi U H 3 f 

Stearin Water Stearic acid Glycerin 

This reaction, it will be noticed, is very similar to that by 
which soap is formed when lye is employed instead of water, as 
explained in Note 4. 

Note 15: 

j 

Soda ash and soda crystals consist essentially of carbonate 
of soda. The soda ash is anhydrous, and may be of very vari¬ 
able degrees of purity; the crystals are obtained by crystallizing 
them out from a strong solution of soda ash in water and are 
much purer than the soda ash from which they are made, but the 
alkali in them is combined with water of crystallization. 

“Caustic soda ash” is a carbonate of soda containing a pro¬ 
portion (more or less) of caustic soda. Ordinary ash contains 
but little caustic. Crystallized soda contains about 63 per cent 
of water and 37 per cent of carbonate of soda. The impurities 
of soda ash made by the Leblanc process of alkali manufacture 
consist chiefly of sulphate of soda, silicate of soda, common salt, 
caustic soda, carbonate of lime, sand, iron, etc. The product of 
the Ammonia process is very much purer, and free from caustic 
soda. 


Appendix. 


449 


Note 16: 

Fats consist of carbon, hydrogen, and oxygen, in about the 
following- proportions (varying with the kind of fat): Carbon 
78 parts, hydrogen 12 parts, oxygen 10 parts. 

Note 17: 

The crystals of sal soda formed by the process as described 
in the chapter devoted to that subject have the composition 
Na s COs+ 10H 2 O; in hot weather Na 2 C0 3 -{-8H 2 0 may form instead. 

Note 18: 

Carbonate of lime has the composition Ca C0 3 ; when burnt 
it becomes CaO; on adding water to the latter there forms the 
hydrate CaH 2 0 2 . 

Note 19: 

The reaction of caustic soda and ammonium chloride is ex¬ 
pressed as follows: 

NH 4 C1 -f NaOH = NaCl + NH 3 + ' 1I 2 0 
Amm. chloride Caustic soda Sodium chloride Ammonia Water. 

In the case of ammonium sulphate the reaction is: 
2(NH 4 )S0 4 +> 2NaOH = Na 2 S0 4 + 2NH 3 + 2H 2 0 

Amm. sulphate Caustic soda Amm. sulphate Ammonia Water. 

Analogous reactions occur also with carbonate of soda in 
place of the caustic. 

Note 20: 

The development of oxygen from the reaction of acids on bi¬ 
carbonate of potash (or soda) is exemplified by the following: 
K 2 Cr 3 0 7 + 4H 2 S0 4 = K 2 S0 4 + Cr 3 (S0 4 ) 3 = 4 H 4 0+30 

Pot. Bichromate Sulph. acid Pot. Sulph. Chr. alum Water Oxygen. 










































. 

. 

' 








































































































































INDEX. 


Adulteration of fats and oils. 35 

Alcohol. 84 

Alcohol test as to its origin. 413 

Alkalies. 23, 72 

Alkali required for saponification. 437 

Almond oil. 66 

Allspice oil. 320 

Alum. 83 

Ambergris. 321 

Ambrette seed. 321 

Anethol. 321 

Anise Aldehyde. 321 

Anise oil.;. 321 

Antiseptic shaving soap. 370 

Appendix. 443 

Arrangement of factory. 87 

Artificial colors and shades. 314 

Artificially figged Soap. 247 

Artificial oil sassafras.'. 321 

Artificial oil wintergreen. 321 

Aubepine. 322 

Avoirdupois weight. 439 

Balsams. 322 

Bay oil. 322 

Benzoin. 322 

Bergamot oil. 322 

Birch oil. 322 

Bitter almond oil. 323 

Bleaching cocoanut oil. 50 

grease. 46 

linseed oil. 62 

palm oil. 53 

rosin. 69 

soap. 61 

tallow.. • *. 43 






































452 


Index. 


Page. 

Blue mottled. 229 

Boiled-down soap....180, 211 

Boiled shaving soap. 3(59 

Boiling process.181, 249 

Boiling down. 215, 221 

Borax. 82 

Borax tests for earthy impurities. 414 

alum.. 414 

carbonates and sulphates. 414 

salt. 415 

soda. 415 

Bunching.188, 218 

Cananga oil. 324 

Caraway seed oil. 324 

Caraway chaff oil. 324 

Carbolic soap. 294 

Carbolic soap. 375 

Care of the dies. 353 

Cassia oil. 324 

Cassie oil. 324 

Castor oil. 63 

Causticizing alkali. 95 

Caustic grades of Lye. 72, 74 

Caustic soda required for making lye. 437 

Cedar wood oil. 324 

Chipper. 164 

Chipping the soap. 307 

Cinnamon oil. 325 

Citron oil.,. 325 

Citronella oil. 325 

Civet. 325 

Clove oil. 325 

Cocoanut oil. 48 

/ 

Cocoanut oil soap filled with salt solution. 287 

Cold made shaving soap. 368 

Cold process.180, 269 

Coloring. 284 

Coloring soap. 228 

Coloring and perfuming. 313 

Coloring.;_ 313 

Compounding perfume. 319 

Connection with kettles. Ill 

Copaiba Balsam. 325 

Corn oil.,.’. 65 

Cottonseed oil. 57 _ 

Cotton Stearin. 60 

Cottonseed foots. 60 

Coumarin. ••••. 30(5 



















































Index, 



Crown soap. 

Crutchers.. 

Crystal transparent soap. 

Cutters. 

Decomposition by graining-. 

Detergents, various.. 

Dies. 

Dill oil. 

Drying apparatus. 

Early method of milling. 

Effect of soap in washing. 

various fats on soap. 

various lyes on soap. 

water in washing. 

Eschweger. 

Eschweger III. 

Essential oils. 

Eucalyptus oil. 

Eugenol.'. 

Expansion of oils by heat *. 

Fats and Fatty acids. 

Fats and oils. 

Fennel.-. 

Figged soap. 

Filled cocoanut oil soap. 

Filling. 

Filling materials. 

Fish oil. 

Floating soap. 

Formation of soap... 

Formulas for various cold made soaps. .. 

F rames. 

Framing. 

Free fatty acids in fat. 

Fuller’s Earth. 

Fuller's fat. 

Gall soap. 

Gaultheria.. 

Geraniol. 

Geranium oil. 

German Mottled. 

Ginger grass oil. 

Glycerin. 

Glycerin and its recovery from waste lye 

Glycerin lime in. 

adulterated.. 

. amount of in waste lye. 

Glycerin soap. 


Page. 

. 243 

. 116 

. 364 

.• 135 

. 255 

. 29 

. 149 

. 326 

. 141 

. 304 

. 28 

. 34 

74, 76, 78, 227 

.. 28 

. 223 

. 229 

.. 415 

. 326 

. 326 

. 438 

.. 24, 31 

. 419 

. 326 

. 245 

. 287 

. 283 

. 79, 200, 201 

. 64 

.179, 264, 357 

. 25 

. 286 

. 127 

197, 207, 217 

. 422 

. 83 

. 65 


326 

326 

327 
212 
327 
422 
395 
422 

422 

423 
290 



















































454 


Index. 


Glycerin transparent soap... 

Graining. 

Grease. 

Guaiacum wood oil. 

Half boiling process. 

Half boiled shaving soap.... 

Half boiled tooth soap. 

Hand stamps. 

Hard soap. 

Hard water soap... .. 

Harness soap. 

Heliotropine. 

Horse fat. 

Imperial measure. 

Infusorial Earth. 

Jonone. 

Kettle connections. 

Kettles. 

Kuro-moji oil. 

Lanolin. 

Lanolin soap. 

Lard. 

Laundry soap. 

Laundry soaps. 

Laurie acid. 

Lavender... 

Lemon grass oil. 

Lemon oil. 

Lilacine. 

Lime. 

Lime oil... 

Linaloe oil. 

Linalool. 

Linoleic acid. 

Linseed oil... 

Lye. 

Lye apparatus. 

Lye tank. 

Mace oil. 

Marbled castile. 

Marbling. 

Margaric acid. 

Marjoram oil. 

Medical soap. 

Melissa oil. 

Melting trough. 

Metal polishing soap. 

Metric weights and measures 


Page. 

. 364 

. 190 

. 45 

. 327 

.181, 257 

. 369 

. 372 

... 162 

. 381 

. 179 

. 374 

. 327 

. 66 

. 439 

. 83 

. 327 

. Ill 

. 101 

. 327 

. 63 

. 291 

. 47 

. 137 

. 291 

. 33 

. 327 

. 329 

. 328 

. 329 

. 85 

. 329 

.329 

. 329 

. 33 

. 62 

71, 73, 226, 237, 275, 277 

. 95 

. 89 

. 329 

. 219 

. 284 

. 33 

. 330 

. 387 

. 330 

. 98 

. 374 

. 438 



















































Index. 


455 


Page 

Mill. 165 

Milled soap. 182 

Milled soaps. 303 

Milled tooth soap. 372 

Milling process. 307 

Mineral soap stock.’. 82 

Mirbane. 330 

Mixing and saponification. 221 

Modification of Eschweger. 232 

Mosaic soap. 295 

Musk. 330 

Myrcia. 330 

Myristic acid. 33 

Natural color of soap.. 314 

Nature of soap. 23 

Neroli. 331 

Nerolin. 331 

Nigre. 201 

Nutmeg oil. 331 

Oenantkic ether. 331 

Oleic acid. 6G, 213 

Oleic acid. 33 

Olibanum oil. 331 

Olive oil. 56 

Olive oil foots.•. 56 

Opoponax oil. 331 

Orange oil. 331 

Origanum oil. 331 

Orris root. 332 

Orris root oil. 332 

Palmarosa. 332 

Palmitic acid. 33 

Palm Kernel oil..... • 55 

Palm oil. 51 

Patchouly oil. 332 

Peanut oil. 64 

Peppermint oil.332 

Perfumes for laundry soap. 340 

(boiled) milled soap.• 345 

cold-made soap. 341 

Perfuming. 284 

Perfuming.. 370 

Perfuming . 319 

Perfuming milled soap. 310 

Peru Balsam. 333 

Pennyroyal oil. 332 

Pine needle oil. 333 

Pinenta oil. 333 


l 





















































456 


Index. 


Plodder. 

Potash. 

Powder mills.. 

Presses. 

Pressing the soap. 

Process of making cold made soap... 

Pumps. 

Pure cocoanut oil soap. 

Rancidity of fats and oils. 

Red mottled castile. 

Red oil.. 

Remelted soap. 

Remelters. 

Remelting soap. 

Rendering fats. 

Reunion. 

Rhodinol. 

Rhodium. 

Rose geranium. 

Rosemary oil. 

Rose oil. 

Rosewood oil.. 

Rosin. 

Rosin soap. 

Rosin soap.. 

Rue oil. 

Safety device for pressing. 

Safrol. 

Sage oil. 

Sal soda. 

Sal soda making. 

Sal soda tank. 

Salt. 

Salt water soap. 

Sand soap. 

Santal wood oil. 

Saponification... 

Sassafras oil. 

Scouring soaps. 

Scraps. 

Selection and preparation of perfumes 

Selection of stock and methods. 

Settled soap. 

Settling. 

Settling tank. 

Shaving soap. 

Shaving soap. 

Shaving soap. 


Page. 

. 166 

. 77, 82, 227 

. 170 

. 142 

. 351 

. 289 

. 112 

. 286 

. 35 

. 375 

. 66 

. 183 

. 116 

. 299 

. 38 

. 327 

. 333 

. 333 

. 333 

. 333 

. 333 

. 334 

. 68 

. 292 

.185, 264 

. 334 

. 160, 161 

. 334 

. 334 

.82, 227 

. 389 

. 127 

. 76, 227 

. 376 

. 373 

. 334 

41, 67, 186, 205, 213, 224 

. 335 

. 272 

. 204 

. 337 

.:. 173 

. 185 

. 195 

. 99 

. 175 

. 367 

. 367 


I 


If 


















































Index. 


457 


Silicates .80, 227, 258 

Slabbers. 135 

Soap, action of... 28 

amount of fatty acids in. 424 

antiseptic shaving. 370 

blue mottled. 229 

boiled. .. 131 

boiled down.180, 211 

boiled shaving. 3(59 

carbolic. 294, 375 

cocoanut oil filled with salt solution. 287 

cold-made.180, 269 

cold-made process. 239 

cold-made shaving. 368 

crown. 243 

crystal transparent. 364 

Eschweger.. 223 

Eschweger III..<. 229 

figged.245, 247 

filled cocoanut oil. 287 

filling. 425 

floating.179. 357 

floating. 357 

formation of. 25 

formulas for various cold-made. 286 

free alkali. 426 

from different stocks. 34 

gall. 377 

general remarks on boiling. 247 

German mottled. 212 

glycerin. 290 

glycerin transparent. 364 

glycern in. 427 

half-boiled. 181 

half-boiled. 257 

cocoanut oil. 266 

floating. 264 

for milling. 262 

mottled.... 263 

rosin. 264 

tar. 265 

white. 261 

half-boiled shaving. 369 

half-boiled tooth. 372 

hard. 381 

hard water. 179 

harness. 374 






















































458 


Index. 


Soap, lanolin. 

laundry. 

lye for cold-made. 

marbled castile. 

medicinal. 

metal polishing. 

milled. 

milled tooth. 

modified Eschweger. 

mosaic. 

nature of. 

natural color of. 

perfumes for laundry. 

cold-made. 

(boiled) milled. 

perfuming milled. 

pressing the. 

properties of soft. 

pure cocoanut oil. 

remelted. 

remelting. 

rosin. 

rosin in. 

salt water. 

sand. 

scouring. 

settled. 

shaving. 

soft. 

special. 

special properties of. 

stock. 

stock for milled. 

stock used. 

sugar in. 

sulphur. 

superfatted. 

surgical. 

tallow and cocoanut oil. 

tar. 

textile. 

toilet. 

tooth. 

transparent. 

transparent with sugar. 

rosin and sugar 

without alcohol. 

glycerin. 


Page. 
.... 291 
173, 291 
.... 74 

.... 219 
.... 378 
.... 374 
182, 303 

. 372 

.... 232 
.... 295 
.... 23 

.... 314 
.... 340 
.... 341 
.... 345 

.310. 

.... 351 
... . 235 
.... 286 
.... 183 
.... 299 
185, 292 
.... 426 
.... 376 
.... 373 
.... 375 
.... 182 
175, 367 
235, 381 
.... 357 
.... 179 
.... 60 
.... 305 
.... 426 
.... 426 
.... 383 
.... 382 
.... 384 
.... 287 
293, 376 
.... 176 
.... 174 
177, 370 
179, 359 
.... 365 
.... 365 
.... 366 
.... 366 


















































In dex. 


459 


Soap, transparent tilled with salts.... 

unsaponified fat in. 

utilizing scraps of cold. 

. water in. 

white. 

white boiled-down. 

white castile. 

white settled. 

yield of hard... 

Soap factor)'-. 

Soap stock. 

Soda and potash. 

Soft soap. 

Soft soap. 

Spearmint oil. 

Special properties of soap. 

Special soaps. . 

Spike. 

Star Anise oil. 

Starch. 

Steam Separator. 

Steam syphon. 

Stearic acid. 

Stock. 

Stock blower. 

Stock for milled soap. 

Purity of. 

temperature for mixing. 

Storax... 

Strengthening. 

Strunz’s lye apparatus .' 

Substances for obtaining perfumes.... 

Sulphur soap . 

Superfatted soaps. 

Surgical soap. 

Table of different thermometric scales 

Tables etc. 

Talc. 

Tallow. 

Tallow. 

Tallow and cocoanut oil soap. 

melting point of. 

titer test of. 

Tar. 

beech. 

juniper. 

pine. 

Tar in general. 


Page. 

. 366 

. 425 

. 294 

. 424 

. 275 

. 220 

. 208 

. 205 

. 251 

. 87 

. 60 

. 427 

. 235 

. 381 

. 335 

. 179 

. 357 

. 335 

. 335 

.81, 200 

. 170 

. 94 

. 32 

. 273 

. 99 

. 305 

. 273 

. 299 

. 335 

194, 207, 220 

. F 

.320 

. 383 

. 382 

. 384 

. 440 

. 437 

. 79 

. 42 

. 419 

. 287 

. 420 

. 420 

. 432 

. 432 

. 432 

. 432 

. 433 


# 


















































400 


Index. 


Page. 

Tar oil. 335 

Tar soap. 293 

Tar soap. 370 

Temperature of w’et steam. 438 

Terpineol.:. 335 

Testing sodium carbonate. 430 

potassium . 430 

caustic soda and potash. 430 

soda. 431 

Tests for adulterated fat.•. 37 

strength of lye. 71 

Textile soap .. 170 

The simpler tests and examinations in the soap factory. 411 

for water in it. 414 

The thermometer. 439 

Thyme oil.;. 335 

Tincture of ambergris. 339 

balsam of peru. 339 

benzoin. 339 

civet. 339 

musk. 338 

orris root. 340 

Storax. 339 

tolu. 340 

vanilla.•. 340 

Toilet soap. 174 

Tolu balsam. 330 

Tooth soap .*.. 177 

Tooth soap . 370 

Transparent soap.179, 359 

Transparent soap with sugar. 305 

rosin and sugar. 305 

without alcohol. 300 

glycerin.,. 300 

filled with salts. 300 

Tripoli. 83 

Troy weight U. S. 439 

Utilizing nigre. 203 

Utilizing scraps. 204 

Utilizing scraps of cold soaps. 294 

Vanillin. 330 

Verbena oil.'. 330 

Vetiver oil. 336 

Washing powder. 385 

Waste lye. 250 

Water in fats. 421 

Water in soap... 20, 85 

Water used for washing. 28 



















































Index. 


461 


Page. 

White boiled-down soap. 220 

White castile. 208 

White settled soap.*. 205 

White soap. 275 

Wine measure U. S. 489 

Wintergreen oil. 386 

Wool Grease . 63 

Yield of hard soap. 251 

Ylang ylang. 337 






































































































































































































































































































































































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